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Published in last 1 year |  In last 2 years |  In last 3 years |  All Please wait a minute... For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select Effect of nickel on thermal fatigue properties of novel hot working die steel Cheng Xi, Gu Pengcheng, Zeng Yan, Wu Xiaochun Heat Treatment of Metals    2023, 48 (11): 55-61.   doi:10.13251/j.issn.0254-6051.2023.11.009 Abstract （232）      PDF （4151KB）（46）       Knowledge map    Thermal fatigue test of SDDVA steel and a novel hot work die steel SDYZ1 was carried out by Uddeholm self-constrained thermal fatigue test method. The surface morphology, cross-section crack, microstructure and hardness of the materials after thermal fatigue were compared and analyzed. The effect of nickel element on the cold and thermal fatigue properties of the material was discussed. The results show that compared with the SDDVA steel, the number of cracks in the SDYZ1 steel is obviously less, the depth is shallower, and the degree of high temperature surface softening is smaller. This is mainly due to the fact that Ni element accumulates near grain boundaries and carbides, which has a pinning effect on carbide growth, and the SDYZ1 steel has higher high temperature strength, which can resist crack propagation. The SDYZ1 steel precipitates carbides with smaller size during thermal fatigue, and the accumulation of carbides at grain boundaries can effectively hinder grain growth, thereby improving the fatigue resistance of the material. Through transmission observation and analysis, the main forms of coarse carbide particles after thermal fatigue of the SDYZ1 steel are irregular spherical and slender rods, and the main types are M23C6 and M6C, and the size of carbides in the SDYZ1 steel is smaller than that in the SDDVA steel. Reference | Related Articles | Metrics Select Measurement of CCT curves and carbide intergranular precipitation temperature of 4Cr5Mo2V hot-working die steel Gao Xingcheng, Wu Boya, Wu Xiaochun Heat Treatment of Metals    2024, 49 (9): 72-79.   doi:10.13251/j.issn.0254-6051.2024.09.012 Abstract （221）      PDF （5564KB）（36）       Knowledge map    Microstructure and hardness of 4Cr5Mo2V steel at different cooling rates were observed and measured by using thermal expansion meter, resistance meter and hardness tester, combined with scanning electron microscope and energy dispersive spectroscopy. CCT curves of the tested steel were plotted, and the temperature of carbide intergranular precipitation in the steel was determined. The results show that as the cooling rate decreases, the hardness decreases and the microstructure transforms into martensite, bainite and pearlite in sequence. The critical cooling rates for pearlite and bainite transformation are 0.015 ℃/s and 0.25 ℃/s, respectively. When the cooling rate is not greater than 0.25 ℃/s, carbides precipitate along the grain in the steel, and as the cooling rate decreases, the temperature of carbide precipitation along the grain increases. At a cooling rate of 0.01 ℃/s, the highest precipitation temperature is 1022 ℃. Reference | Related Articles | Metrics Select Element segregation and homogenization heat treatment of DIEVAR hot working die steel Du Simin, Cheng Wenxiong, Hu Fengrong, Ren Jinqiao, Cui Xiaokang, Zhou Zhiming Heat Treatment of Metals    2024, 49 (7): 139-145.   doi:10.13251/j.issn.0254-6051.2024.07.021 Abstract （198）      PDF （6795KB）（29）       Knowledge map    As-cast microstructure, precipitated phases and element segregation characteristics of DIEVAR hot working die steel electroslag ingot were analyzed by the means of optical microscope (OM), scanning electron microscope (SEM/EDS), electron probe (EPMA), Thermo-Calc thermodynamic calculation. Then the effect of homogenization heat treatment on the microstructure and carbide and element distribution was studied. The results show that the as-cast dendrite structure of the tested steel is well developed, and the secondary dendrites are obvious. The Cr and Mo and V elements are inter-dendritically enriched, and the segregation order is Mo>V>Cr. The interdendritic precipitated phases are M23C6, M6C and MC carbides. With the increase of homogenization temperature and the extension of holding time, the dendrite microstructure gradually becomes fuzzy and even disappears, and the carbide redissolution forms a certain element diffusion zone and gradually diffuses until it is fully redissolved into the matrix, the element diffusion rate is Cr>Mo>V during the homogenization heat treatment. According to dendrite morphology, carbide redissolution, element diffusion and residual segregation index of Mo element after homogenization heat treatment, and considering the actual industrial production cost, the optimal homogenization heat treatment process of the DIEVAR steel is 1280 ℃×8 h. Reference | Related Articles | Metrics Select Research status of high-temperature mechanical properties and deformation mechanism of FeMnCoCrNi high-entropy alloy Sheng Jian, Li Dazhao, Yan Zhijie, Bai Shaobin, Chen Yongan, Xie Ruofei Heat Treatment of Metals    2024, 49 (10): 211-219.   doi:10.13251/j.issn.0254-6051.2024.10.035 Abstract （187）      PDF （4238KB）（80）       Knowledge map    As a class of emerging advanced metal materials in recent years and based on the unique multi-principal element alloy design concept, high-entropy alloys (HEAs) are expected to break through the performance limit of traditional single-principal element alloys. Among them, FeMnCoCrNi HEA is one of the most widely studied systems with excellent mechanical properties and broad application prospects. The unique “four core effects” of HEAs were firstly introduced, including high entropy effect, lattice distortion effect, hysteresis diffusion effect and cocktail effect. Secondly, the research status of FeMnCoCrNi high entropy alloy in high temperature tensile properties, high temperature creep properties and corresponding deformation mechanisms was reviewed. Reference | Related Articles | Metrics Select Effect of Zn/Mg ratio on microstructure, mechanical properties and corrosion resistance of 7075 aluminum alloy He Zongzheng, Wu Mingdong, Yuan Shuo, Yao Shuwei, Xiao Daihong, Huang Lanping, Liu Wensheng Heat Treatment of Metals    2024, 49 (5): 1-9.   doi:10.13251/j.issn.0254-6051.2024.05.001 Abstract （185）      PDF （9223KB）（127）       Knowledge map    Effect of Zn/Mg ratio (mass fraction) on microstructure, mechanical properties, and corrosion resistance of 7075 aluminum alloys was investigated by means of optical microscope, scanning electron microscope, transmission electron microscope, tensile test, microhardness test and corrosion test. The results show that with the increase of Zn/Mg ratio from 1.76 to 2.90, the grain size of the as-cast alloy increases, the T6 age-hardening rate of the alloy is accelerated, and the time to reach peak hardness is shortened. The increase in Zn/Mg ratio results in a decrease in the recrystallization rate of the T6 peak-aged alloy and an increase in the percentage of the low-angle grain boundaries. The tensile strength of the alloy under the T6 peak-aging treatment with the Zn/Mg ratio of 2.10 is 634 MPa, the yield strength of the alloy is 588 MPa, and elongation is 8.4%. The tensile strength of the T74 aged alloy is 613 MPa, yield strength is 542 MPa, and elongation is 8.9%, and alloys with Zn/Mg ratio of 2.10 in both aging states exhibit good strength while maintaining high elongation. The corrosion resistance of the aged alloy decreases as the Zn/Mg ratio increases from 1.76 to 2.90. The corrosion resistance of the alloy after T74 aging treatment is better than that of the alloy under the T6 peak-aging state. Reference | Related Articles | Metrics Select Effect of Ni content on microstructure and mechanical properties of quenched and tempered 40CrNiMo steel Guan Yunqi, Li Liang, Hu Wenxiang, Shi Zhengliang, Xu Jia Heat Treatment of Metals    2022, 47 (9): 245-249.   doi:10.13251/j.issn.0254-6051.2022.09.042 Abstract （162）      PDF （632KB）（44）       Knowledge map    Effect of Ni content on microstructure, volume fraction of retained austenite, hardness, tensile strength and impact property at room temperature of quenched and tempered 40CrNiMo steel was studied by means of OES, SEM, XRD and mechanical testing instruments. The results show that with the increase of Ni content from 1.346% to 1.618%, the microstructure and content of retained austenite have no obviously change, while the lattice distortion of α-Fe increases. The hardness of the tested steel tempered at different temperatures increases by 5-10 HV. The tensile strength of the high Ni content steel tempered at 450 ℃ is 78 MPa higher than that of the low Ni content steel, meanwhile the increase of tensile strength decreases with the increase of tempering temperature. However, under the condition that the retained austenite content is almost unchanged, the increase of Ni content reduces the impact absorbed energy of the steel tempered at 450 ℃ and 500 ℃ by about 50%. Reference | Related Articles | Metrics Select Phase transformation behavior during continuous cooling of Cr8 back-up roll steel Guo Yafei, Li Zhilong, Zhang Bo, Li Jie, Pang Qinghai Heat Treatment of Metals    2023, 48 (8): 47-51.   doi:10.13251/j.issn.0254-6051.2023.08.008 Abstract （158）      PDF （4443KB）（51）       Knowledge map    In order to investigate the phase transformation behavior of Cr8 back-up roll steel during the continuous cooling process, the phase transformation parameters of the Cr8 back-up roll steel at different cooling rates were measured by Formastor-FⅡ automatic phase transformation analyzer. The CCT curves was established by thermal expansion method and metallographic method, and the influence of different cooling rates on microstructure and hardness of the Cr8 back-up roll steel was analyzed. The results show that the microhardness of Cr8 back-up roll steel increases gradually with the increase of cooling rate in the range of 2-60 ℃/min, and the hardness value increases from 238 HV2 to 570 HV2. The supercooled austenite transforms into a mixed structure containing pearlite when the cooling rate is less than 8 ℃/min. The pearlite transformation disappears and the supercooled austenite transforms into bainite+martensite or single martensite with higher hardness when the cooling rate is between 8 ℃/min and 60 ℃/min. Compared with Cr5 steel, the supercooled austenite of the Cr8 back-up roll steel has better stability, the steel has lower critical cooling rate and good mechanical properties, and is an ideal material for manufacturing large backup roll forgings. Reference | Related Articles | Metrics Select CCT curves and impact property of Q355D hot rolled H-steel Wang Wenzheng, Ma Yongfu, Ma Jinhong, Zhang Guiying, Tian Yaqiang, Cheng Xinchao, Li Hongbin, Chen Liansheng Heat Treatment of Metals    2023, 48 (1): 127-132.   doi:10.13251/j.issn.0254-6051.2023.01.022 Abstract （140）      PDF （574KB）（49）       Knowledge map    Continuous cooling transformation rule of Q355D hot-rolled H-steel was investigated on Glebble-3500 thermal simulation test machine by means of expansion method and metallography hardness method. In addition, static CCT curves were obtained. The results show that from the CCT curves, the microstructure of the steel is composed of ferrite and pearlite when the cooling rate is less than 1 ℃/s, ferrite, pearlite and bainite when the cooling rate is 1-10 ℃/s, and ferrite, bainite and martensite when the cooling rate is 20-50 ℃/s. With the increase of cooling rate, the hardness of the Q355D hot-rolled H-steel increases, and the hardness increases from 171 HV0.2 to 301 HV0.2. According to CCT curves, different rolling experiment schemes are worked out. When the total reduction is 75%, the strain rate is 0.3 s-1 and the deformation temperature is 1150 ℃, the ferrite grain size of the tested steel is 8.13 μm, and the impact absorbed energy at -20 ℃ is 146 J, with the best performance. Reference | Related Articles | Metrics Select Research progress of low alloy martensitic wear-resistant steel Li Zhongbo, Wu Zhifang, Wu Run Heat Treatment of Metals    2024, 49 (7): 132-138.   doi:10.13251/j.issn.0254-6051.2024.07.020 Abstract （138）      PDF （1095KB）（52）       Knowledge map    Research progress of low alloy martensitic wear-resistant steel was reviewed, mainly involving composition design, heat treatment process and its on microstructure and mechanical properties, and wear resistance. Composition design mainly adopts a small number of multi-component system, heat treatment processes include reheat quenching-tempering treatment, direct quenching-tempering treatment, subtemperature quenching-tempering treatment, quenching-partitioning treatment and quenching-partitioning-tempering treatment. By controlling the structure shape and distribution, the hardness and toughness can be matched reasonably. The wear resistance is improved by adjusting chemical composition, refining grain, optimizing rolling cooling process and proper tempering. Reference | Related Articles | Metrics Select Effect of composite addition of trace amounts of Mn, Zn and Ti on microstructure and mechanical properties of Al-Cu-Li-Mg-Ag-Zr alloy Xu Qing, Yin Dengfeng, Wang Hua, Xie Kaiwen, Song Zhuanzhuan Heat Treatment of Metals    2024, 49 (11): 1-9.   doi:10.13251/j.issn.0254-6051.2024.11.001 Abstract （134）      PDF （5872KB）（101）       Knowledge map    Effect of composite addition of trace amounts of Mn, Zn and Ti on the microstructure and mechanical properties of Al-Cu-Li-Mg-Ag-Zr alloy was studied by using tensile testing machine, metallographic microscope, scanning electron microscope and transmission electron microscope. The results show that the composite addition of trace amounts of Mn, Zn and Ti elements can significantly refine the grain structure of the as-cast alloy, and at the same time, the insoluble second phase Al(CuMnFe) in the solution treated alloy is also refined. The composite addition of trace amounts of Mn, Zn and Ti elements can effectively promote the precipitation of the main strengthening phase T1 in the T6 and T8 peak aged Al-Cu-Li-Mg-Ag-Zr alloy, improving the mechanical properties of the alloy. Compared with the T6 peak aged, the amount of T1 phase precipitated in the T8 peak aged Al-Cu-Li-Mg-Ag-Zr alloy significantly increases, the size significantly decreases, the distribution is more uniform and dispersed, and the strength and plasticity are significantly improved. Reference | Related Articles | Metrics Select Effect of thermal deformation on bainite transformation of plastic mould steel SDFT600 Zhang Zheng, Chen Jinlei, Zhang Min, Qiao Junwei Heat Treatment of Metals    2022, 47 (8): 1-6.   doi:10.13251/j.issn.0254-6051.2022.08.001 Abstract （134）      PDF （608KB）（89）       Knowledge map    Effect of thermal deformation on bainite transformation of plastic mould steel SDFT600 during continuous cooling was analyzed by means of thermal simulation machine, thermal dilatometer, scanning electron microscope, etc. The results show that with the parameters suitable for forging production of large plastic mould steel blocks, thermal deformation promotes bainite transformation. At same continuous cooling rate, the bainite transformation start temperature of dynamic CCT specimen is higher than that of static CCT specimen, at cooling rate of 0.5 ℃/s, the temperature difference reaches 96 ℃. Thermal deformation reduces the stability of retained austenite, and at cooling rate of 0.5 ℃/s, the bainite content of dynamic CCT specimen is higher than that of static CCT specimen. When the continuous cooling rate is less than 0.1 ℃/s, the content of retained austenite of dynamic CCT specimen is lower than that of static CCT specimen. Hardness uniformity under thermal deformation condition is better, which is beneficial to the final quality of mould blocks. Reference | Related Articles | Metrics Select Austenite grain distribution law in 34CrNi3MoV steel Zheng Bing, Xu Dong, Wang Yiqun, Wang Xuexi, Zhao Hongyang, Ju Dongying Heat Treatment of Metals    2023, 48 (7): 1-7.   doi:10.13251/j.issn.0254-6051.2023.07.001 Abstract （122）      PDF （2733KB）（134）       Knowledge map    Effects of different holding temperature and holding time on austenite grain growth of 34CrNi3MoV steel were studied. The effects of holding temperature and holding time on average grain size, major axis and minor axis were analyzed by means of metallography. The results show that in the Gaussian distribution equation, the standard deviation and expectation increase with the increase of holding temperature and holding time. The size of the major axis and minor axis of grains is closely related to the average size, and the ratio has a simple linear relationship. During the grain growth, the ratio of the major axis to the minor axis basically remains unchanged. The distribution probability expressions of average grain size, major axis size and minor axis size are obtained by regression. At the same time,a new way of thinking and possible explanation for the heredity in materials science in terms of mathematical laws is provided. Reference | Related Articles | Metrics Select Effect of Cu on mechanical properties of 390 MPa grade CrNiMo series low-alloy ship steel plates Li Weixian, Peng Wei, Hu Jie, Liu Tengshi, Zhou Luhai, Dong Han Heat Treatment of Metals    2024, 49 (4): 1-7.   doi:10.13251/j.issn.0254-6051.2024.04.001 Abstract （117）      PDF （5141KB）（114）       Knowledge map    CrNiMo low-alloy marine steels without Cu(961-Base) and with 1wt% Cu(961-Cu) quenched twice and then tempered at high temperature were prepared, and then the effect of Cu on microstructure, mechanical properties, precipitated phase and texture characteristics of the steel was investigated by thermal dilatometer, optical microscope(OM), scanning electron microscope(SEM), electron backscatter diffractometer(EBSD) and transmission electron microscope(TEM). The results show that the Ac1 and Ac3 temperatures of the 961-Base steel are 767 ℃ and 905 ℃, and that of 961-Cu steel are 762 ℃ and 895 ℃, respectively. The ferrite/bainite transformation temperatures of the 961-Cu steel are lower than that of the 961-Base steel. The microstructure of the tested steels after heat treatment is dominated by lath bainite(LB) and a small amount of quasi-polygonal ferrite(QPF). The lath of the 961-Cu steel is more refined, which increases the proportion of large-angle grain boundaries by 6.8% and is more beneficial to hinder crack propagation. Compared with that of the 961-Base steel, the yield strength and tensile strength of the 961-Cu steel are increased by 84 MPa and 68 MPa, respectively, and the low-temperature impact absorbed energy are increased from 220 J to 267 J. The impact fracture of the tested steels is dominated by the shear lip and fiber zone, with the 961-Cu steel having a greater shear section ratio. The Cu-rich phase (fcc structure) is non-uniformly precipitated in the matrix and on dislocation line in the form of globular or rods, producing a precipitation strengthening effect. Both the tested steels are characterized by α and γ textures, with the 961-Cu steel containing a higher proportion of γ textures that is conducive to deformation. Reference | Related Articles | Metrics Select Carbide evolution law of high chromium and high vanadium powder metallurgy tool steel M390 during austenitizing Deng Jinqiang, Zhang Qinyi, Chen Jun, Wu Dong, Liu Wei, Zhou Hongfeng Heat Treatment of Metals    2023, 48 (11): 1-7.   doi:10.13251/j.issn.0254-6051.2023.11.001 Abstract （115）      PDF （4216KB）（128）       Knowledge map    Evolution of carbides in the M390 steel during different austenitizing processes was studied using analysis methods such as SEM-EDS, TEM, and Image-Pro Plus. The results show that under the austenitizing conditions of heating at 1075-1150 ℃ and holding for 15-120 min, the volume fraction and average size of carbides in the M390 steel show a decreasing trend as the quenching temperature increases. At the same quenching temperature, with the prolongation of holding time, the amount of carbides decreases as a whole, the average size of carbides decreases first and then increases, while the amount of small carbides and hardness increase first and then decrease. The types of undissolved carbides in high temperature oil quenched steel are mainly M7C3 and M8C7. During austenitizing, the change of carbides in the M390 steel is mainly the dissolution, growth and dissolution of M7C3. Reference | Related Articles | Metrics Select Effect of carbon content and cooling rate on quenching residual stress of steel parts Li Yang, Zhang Jianwei, Zhu Pengkai, Yang Yang Heat Treatment of Metals    2022, 47 (6): 192-195.   doi:10.13251/j.issn.0254-6051.2022.06.036 Abstract （115）      PDF （3027KB）（37）       Knowledge map    Relationship between surface residual stress and carbon content as well as the cooling rate of SAE8620, SAE8625 and SAE8627 steel bars with diameter of ø12 mm and the length of 50 mm after quenching was studied. The results show that the residual stress is compressive stress and the value is about 200-600 MPa. The value of compressive stress decreases with the increase of carbon content and the cooling rate,while the relationship between compressive stress value and core hardness is just the opposite. The higher the cooling rate is, the smaller the residual compressive stress is for the same core hardness of the same carbon content test piece. Thus, adopting lower cooling rate is beneficial to increase the residual compressive stress on the surface. Reference | Related Articles | Metrics Select Microstructure of 11%Cr ferritic/martensitic steel in normally heat-treated state before and after irradiation Wo Jianxing, Shen Yinzhong Heat Treatment of Metals    2025, 50 (1): 6-11.   doi:10.13251/j.issn.0254-6051.2025.01.001 Abstract （109）      PDF （2775KB）（82）       Knowledge map    The microstructure of 11%Cr ferritic/martensitic steel in the normally heat-treated state before and after irradiation was experimentally studied by using transmission electron microscopy and energy dispersive spectroscopy. The results show that the primary microstructure of the 11%Cr ferritic/martensitic steel before and after irradiation consists of tempered martensitic along with a small amount of δ-ferrite. Before irradiation, a small amount of precipitates with a relatively small size are present at martensite boundaries and within martensite laths. Some irregular, blocky, large black particles are present at the interface of δ-ferrite and matrix. There are no precipitates within δ-ferrite grains. After irradiation, a large number of rod-like and blocky precipitates appear at the boundaries and interior of the martensitic lath, while the number and size of precipitates significantly increase compared to that before irradiation. The number of irregular blocky black particles at the interface of δ-ferrite and matrix increase compared to that before irradiation. Inside the δ-ferrite, a large number of blocky and needle-like precipitates are formed which may be Cr-rich nitrides, Cr-rich carbonitrides and Fe-W type precipitates. After irradiation, the precipitates inside the martensitic laths are Cr-rich M23C6 phase. Compared with the Cr-rich M23C6 phase before irradiation, the Cr and Ta contents in the M23C6 phase slightly decrease, while the Fe and Nd contents slightly increase after irradiation. However, overall, the changes in the average metal element composition of the Cr-rich M23C6 phase are relatively small. Reference | Related Articles | Metrics Select Effect of vanadium on microstructure and properties of high chrome alloy casting infiltration layer Yue Jianguo, Liu Wangyang, Chen Chong, Wei Shizhong, Diao Xiaogang Heat Treatment of Metals    2022, 47 (6): 178-185.   doi:10.13251/j.issn.0254-6051.2022.06.034 Abstract （108）      PDF （8432KB）（28）       Knowledge map    Some high chromium alloy casting infiltration composite layers with various vanadium contents were prepared on the surface of ZG45 steel by vaccum evaporative pattern casting process. Effect of different vanadium contents on microstructure of the layers was studied by using scanning electron microscopy (SEM), energy spectrometer (EDS)and X-ray diffraction (XRD), while that on the hardness and wear resistance was researched by using Rockwell hardness tester and the impact wear experiment machine. The results show that the structure of the casting infiltration layer is mainly composed of α-Fe and α-Fe+M7C3+VC eutectic structure. The alloying elements in the transition layer are distributed in gradient, and C, Cr, V elements are diffused from the casting infiltration layer to the matrix. The distribution of C, Cr, V elements coincide with the distribution of carbides. With the increase of vanadium content, the grain is gradually refined, the amount of eutectic carbides is gradually increased, the amount of VC is also increased, and the hardness and wear resistance of the casting infiltration layer is improved. After heat treatment, a large amount of secondary carbides is precipitated. With the increase of V content in the casting infiltration layer, the secondary hardening effect is significantly improved. Reference | Related Articles | Metrics Select Effect of chemical composition on microstructure and deformation behavior of 316L austenitic stainless steel Mo Jinqiang, Feng Guanghong, Xu Mei, Zhang Wei, Li Yang Heat Treatment of Metals    2022, 47 (5): 81-86.   doi:10.13251/j.issn.0254-6051.2022.05.013 Abstract （105）      PDF （562KB）（41）       Knowledge map    Room temperature uniaxial tensile test was carried out by universal testing machine for hot-rolled 316L stainless steel plate with different nickel equivalents, then microstructure of the steel before and after the tensile deformation was observed by scanning electron microscope (SEM) and transmission electron microscope(TEM), and the effect of nickel equivalent(Nieq) on microstructure and properties of 316L stainless steel was explored. The results show that the microstructure at solid solution state is austenite and a small amocmt of high temperature δ phase, the strength decreases with the increase of Nieq, and the plasticity and toughness increase with the increase of Nieq. The tensile fracture is characterized by ductile fracture, and with the increase of Nieq, the number of dimples decreases while the size of dimples increases. The TEM observation shows that no martensitic transformation occurs in the deformed tested steel, when the Nieq is low, the dislocation density in the place with large deformation is high, dislocation interaction occurs, and deformation twins are formed locally. With the increase of Nieq, the density of deformation twin increases, and resulting in crossing and hysteresis. Reference | Related Articles | Metrics Select Effect of alloying of nickel and iron and aging time on phase transformation behaviour of MnCu based damping alloy Niu Hongkang, Wang Diwei, Tian Qingchao Heat Treatment of Metals    2022, 47 (5): 1-6.   doi:10.13251/j.issn.0254-6051.2022.05.001 Abstract （104）      PDF （640KB）（81）       Knowledge map    Three alloys with different composition gradients of Mn-20Cu, Mn-20Cu-5Ni and Mn-20Cu-5Ni-2Fe were prepared, the relationships between elastic modulus and internal friction versus temperature were measured by using a dynamic mechanical analyzer to investigate the effects of chemical composition and aging time on antiferromagnetic transformation and martensitic transformation of the alloys. The results show that the characteristic phase transformation temperature of the three alloys is positively correlated with the square root of the aging time, the alloying elements act on the characteristic temperature by influencing the diffusion of solute atoms during spinodal decomposition and that the l-value describing the coupling strength between applied oscillating stress and phase interface is one of the key factors reflecting the damping alloy material. Reference | Related Articles | Metrics Select Effect of silicon content on microstructure and mechanical properties of heat-resistant nodular cast iron Zhao Jing, Wang Liping, Feng Yicheng, Jiang Wenyong, Wang Lei, Guo Erjun Heat Treatment of Metals    2022, 47 (9): 227-233.   doi:10.13251/j.issn.0254-6051.2022.09.039 Abstract （104）      PDF （631KB）（33）       Knowledge map    The influence of silicon content on microstructure and mechanical properties of heat-resistant nodular cast iron at room temperature and high temperature was studied by means of optical microscope, scanning electron microscope and electronic universal tensile testing machine. The test results show that with the increase of silicon content, the roundness of graphite gradually decreases. When the silicon content(mass fraction, similarly hereinafter) reaches 3.8%, fragmented graphite begins to appear in the matrix, and the spheroidization grade is grade 3. As the silicon content increases from 2.8% to 4.8%, the pearlite content decreases from 51.06% to 8.65%. With the increase of silicon content, the room temperature tensile strength first increases and then decreases, and the elongation decreases gradually. When the silicon content is 3.8%, the tensile strength is 726 MPa and the elongation is 1.6%. With the increase of silicon content, the high temperature tensile strength gradually increases and the elongation decreases gradually. When the silicon content is 4.8%, the tensile strength is 532 MPa and the elongation is 6%. A large number of cleavage planes and river patterns appear in the tensile fracture at room temperature, and the form is brittle fracture. Dimples and tear edges appear in the high temperature tensile fracture, and the tensile fracture form is ductile-brittle mixed fracture. Reference | Related Articles | Metrics page Page 1 of 12 Total 234 records First page Prev page Next page Last page