Effect of thermal exposure on microstructure and mechanical properties of Ti55 alloy

doi:10.13251/j.issn.0254-6051.2024.01.003

Abstract

Abstract: Effect of thermal exposure at 400-800 ℃ on the microstructure and mechanical properties of forged Ti55 alloy was studied. Meanwhile, the fatigue fracture micro morphology characteristics at elevated temperature were analyzed. The results show that the yield strength and tensile strength are basically stable under long-term thermal exposure below 550 ℃, while the elongation decreases with the increase of exposure temperature. Thermal exposure below 800 ℃ does not change the microstructure type of the Ti55 alloy, but with the increase of thermal exposure temperature, the β phase coarsens locally at the α intersection of phase bundles. When exposed above 550 ℃, Si is obviously concentrated in the grain boundary region, and the maximum concentration is up to 1%. With the increase of thermal exposure temperature, the characteristics of high-temperature fatigue fracture of the Ti55 alloy change from transgranular toughness to intergranular brittleness.

Key words: Ti55 alloy, thermal exposure, microstructure, mechanical properties, EPMA, fatigue fracture

CLC Number:

TG156.1

Song Tijie, Wang Changyu, Wang Jue, Yu Yanyan, Lu Zengwei, Jin Dongyan. Effect of thermal exposure on microstructure and mechanical properties of Ti55 alloy[J]. Heat Treatment of Metals, 2024, 49(1): 15-21.

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