热处理对TC18粉末合金微观组织及力学性能影响

Effect of Heat Treatment on Microstructure and Mechanical Properties of TC18 Powder Alloy

采用粉末冶金工艺制备了TC18粉末合金,并基于固溶+时效热处理,系统地研究了固溶温度对合金微观组织和力学性能的影响。研究结果表明,原始态TC18粉末合金的微观组织主要由α相和β相组成。随着固溶温度的增加,初生α相逐渐消失,次生α相发生粗化,同时相间距增大。由于微观组织的变化,导致TC18粉末合金的强度和硬度随固溶温度的增加先增加后降低,延伸率则呈现相反趋势。基于以上结果,进一步讨论和分析了热处理对合金微观组织及力学性能影响的本征关联。

TC18 powder alloy was fabricated by powder metallurgy(PM) route. Further, the influence of solution temperature on the microstructure and mechanical properties of the alloy was systematically investigated based on solution treated and aged process. The results show that the microstructure of PM-fabricated TC18 powder alloy consists of α phase and β phase. With increase of solution temperature, the primary α phase gradually disappears, the secondary α phase coarsens, and the phase spacing increases. As a result, the strength and hardness of the TC18 powder alloy first increase and then decrease with increase of solution temperature, while the elongation shows the opposite trend. Based on the above results, the intrinsic connection between the heat treatment and the microstructure and mechanical performance was clarified.