热处理对新型高强钛合金组织与性能影响研究

A study of heat treatment on microstructures and tensile properties of a new high strength titanium alloy

摘要:

本论文研究了新型高强钛合金（Ti-6Al-6Mo-4V）的微观结构和力学性能。分在α/β和β区固溶处理后，在460℃~620℃5个不同温度下时效6h，研究合金的组织与性能之间的关系。结果表明，α/β区固溶时效处理后的性能与β单相区固溶时效处理后相比，α/β区固溶时效处理后合金获得更好的强度和塑性组合。在850℃（α/β区域）固溶处理以及460℃时效后，合金获得最高的强度为1572MPa，伸长率为2.63％；在620℃时效时，合金的伸长率达到最高为11.46％，但强度较低为1201MPa。经过825℃固溶处理，540℃时效后，该合金获得最好的强度（1328MPa）和伸长率（7.58％）匹配。同时，β区溶液处理后的β晶粒较大，时效后形成细小的二次α相 ,导致强度和塑性较差。

Abstract:

In this paper, the microstructure and mechanical properties of a high strength titanium alloy (Ti–6Al–6Mo–4V) were firstly investigated. The relationship between microstructures and properties of the alloys were investigated after solution treatment at α/β and β regions and then aging at five different temperatures ranging from 460℃ to 620℃ for 6h. The results illustrate the alloys after α/β region solution treatment and aging show a more attractive combination of strength and elongation than β solution treatment and aging. After solution treatment at 850℃ (α/β region) and aging at 460℃, the alloy obtains the highest strength (1572MPa) with elongation (2.63%). When aging at 620℃, the alloy obtains the highest elongation (11.46%) but lower strength (1201MPa). After solution treatment at 825℃ plus aging at 540℃, this alloy reaches a great combination of strength (1328MPa) and elongation (7.58%).Meanwhile, due to the large β grains after β region solution treatment and fine secondary α forms during aging, it does not obtain an attractive strength after β region solution treatment plus aging.