Effect of HIP temperature on microstructure and mechanical properties of TC4 titanium alloy prepared by SLM

doi:10.13251/j.issn.0254-6051.2022.06.027

Abstract

Abstract: Using optical microscope (OM), scanning electron microscope (SEM) and electronic universal testing machine, the effect of hot isostatic pressing (HIP) temperature on the microstructure and mechanical properties of the TC4 titanium alloy formed by laser selective melting (SLM) was investigated. The results show that the cross section microstructure of the TC4 titanium alloy by SLM is composed of equiaxed primary β grains, the longitudinal section microstructure is composed of columnar primary β grains with epitaxial growth. The inside of the grains is dominated by acicular α' martensite phases with different orientations, nano-dot β phase nucleates and grows between the primary martensite. The structure of the TC4 titanium alloy is composed of α phase and β phase when HIP is performed at temperature of the α+β phase region. With the increase of HIP temperature, the lath α-phase coarsens into short rod, the content of β phase increases and coarsens, the tensile strength and yield strength of TC4 shows a decreasing trend, section shrinkage also shows a decreasing trend. When HIP at 910 ℃ with a pressure of 110 MPa for 2 h, the TC4 titanium alloy obtains the best matching of strength and toughness.

Key words: hot isostatic pressing, selective laser melting, TC4 titanium alloy, microstructure, mechanical properties

CLC Number:

TG166.5

Lü Zhoujin, Li Haofeng, Che Lida, Wu Zhanfang, Zhai Yiduo, Cui Xiaomin, Li Xiangyang. Effect of HIP temperature on microstructure and mechanical properties of TC4 titanium alloy prepared by SLM[J]. Heat Treatment of Metals, 2022, 47(6): 138-142.

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