Effect of aging temperature on microstructure and mechanical properties of Ti-4Al-5Mo-5V-6Cr-1Nb titanium alloy

doi:10.13251/j.issn.0254-6051.2025.05.041

Abstract

Abstract: Effect of aging temperature on microstructure and mechanical properties of the Ti-4Al-5Mo-5V-6Cr-1Nb titanium alloy was investigated by means of scanning electron microscope and universal material testing machine, etc. The results demonstrate that there is not much difference in microstructure of the tested titanium alloy at different aging temperatures, exhibiting a typical triple-junction grain boundary structure composed of α phase and β phase. The α phase precipitates primarily in the form of long lamellar, forming a network-like structure that effectively impedes dislocation slip and enhances the mechanical properties of the alloy. The tensile strength of the alloy increases with aging temperature decreasing, reaching a maximum value of 1368 MPa after aging at 520 ℃, Conversely, the elongation, percentage reduction of area and fracture toughness of the alloy gradually decrease. The tensile fracture characteristics indicate a mixed mechanism involving intergranular brittle fracture and ductile fracture. The optimal matching of strength, plastic and fracture toughness is achieved when the alloy is aged at 530 ℃, with the tensile strength of 1311 MPa, yield strength of 1250 MPa, elongation of 4.9%, percentage reduction of area of 8.7% and fracture toughness of 64.84 MPa·m^1/2.

Key words: Ti-4Al-5Mo-5V-6Cr-1Nb titanium alloy, aging, microstructure, mechanical properties

CLC Number:

TG146.2

Chen Suming, Hu Shengshuang, Ji Li, Yan Jiawei, Gao Xiaoying, Zheng Hongfei. Effect of aging temperature on microstructure and mechanical properties of Ti-4Al-5Mo-5V-6Cr-1Nb titanium alloy[J]. Heat Treatment of Metals, 2025, 50(5): 263-267.

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