Ag微合金化对激光粉床熔融Al-Zn-Mg-Cu合金的裂纹抑制作用

doi:10.13251/j.issn.0254-6051.2025.07.010

摘要/Abstract

摘要： 研究了激光粉床熔融(LPBF)技术制备Al-Zn-Mg-Cu合金过程中的缺陷形成机制及裂纹抑制策略。通过调整激光功率和扫描速度,分析了不同能量密度对合金成形质量的影响,并探讨了添加0.4%Ag微合金化对合金微观结构和力学性能的提升作用。结果表明,低能量密度会导致Al-Zn-Mg-Cu合金出现未熔合孔和大尺寸裂纹,而高能量密度虽能减少未熔合孔,但会形成小尺寸气孔。最优LPBF打印工艺参数为激光功率180 W、扫描速度200 mm/s。添加0.4%Ag显著改善了合金的微观结构,扩大了熔池边界的细晶区域,促进了柱状晶向等轴晶转变,有效抑制了裂纹扩展,使合金断裂强度提升至235 MPa,表明Ag的添加对提升合金强度具有积极作用。

关键词: 激光粉床熔融, Al-Zn-Mg-Cu合金, 裂纹抑制, Ag微合金化

Abstract: Defect formation mechanisms and crack inhibition strategies of Al-Zn-Mg-Cu alloy during preparation by laser powder bed fusion (LPBF) were investigated. By adjusting the laser power and scanning speed, the effect of different energy densities on forming quality of the alloy was analyzed, and the enhancing effect of microalloying by adding 0.4%Ag on the microstructure and mechanical properties of the alloy was explored. The results show that low energy density leads to unbonded pores and large cracks in the Al-Zn-Mg-Cu alloy, while high energy density reduces unbonded pores but forms small-sized gas pores. The optimal LPBF printing process parameters are laser power of 180 W and scanning speed of 200 mm/s. The addition of 0.4%Ag significantly improves the microstructure of the alloy, expands the fine-grained region at the melt pool boundary, promotes the transition of columnar grains to equiaxed grains, and effectively inhibits crack propagation, resulting in an increase in fracture strength to 235 MPa, which indicates that the addition of Ag plays a positive role in enhancing the strength of the alloy.

Key words: laser powder bed fusion, Al-Zn-Mg-Cu alloy, crack inhibition, Ag microalloying

中图分类号:

TG146.2

唐辉, 宋斌, 周波, 杨燕. Ag微合金化对激光粉床熔融Al-Zn-Mg-Cu合金的裂纹抑制作用[J]. 金属热处理, 2025, 50(7): 66-72.

Tang Hui, Song Bin, Zhou Bo, Yang Yan. Crack inhibition effect of Ag microalloying on Al-Zn-Mg-Cu alloy prepared by laser powder bed fusion[J]. Heat Treatment of Metals, 2025, 50(7): 66-72.

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