冷却速率对TC21合金超塑变形后显微组织影响  

Effects of heat treatment on microstructure of TC21 titanium alloy after superplastic tensile deformation

作　　者：王鑫[1] 董洪波[1] 朱深亮 

机构地区：[1]南昌航空大学航空制造工程学院,江西南昌330063

出　　处：《材料热处理学报》2016年第5期28-32,共5页Transactions of Materials and Heat Treatment

基　　金：国家自然科学基金(51164029);航空科学基金(2015ZE56011)

摘　　要：对TC21钛合金进行超塑性拉伸和三重热处理试验,研究了TC21合金超塑变形后冷却速率对相变及显微组织的影响。结果表明,第一重热处理冷却速率对显微组织影响最大;当炉冷时α相由β晶界向晶内生长形成魏氏组织,当水冷时形成大片针状α″相互正交的马氏体片层,当空冷时由β晶粒中析出弥散细小的α″相。第二重热处理的冷却速率主要影响次生α相形貌;当炉冷时次生α相形成片层较细薄的魏氏组织,只有当空冷时次生α相才能在弥散细小的α″析出物上形核并生长为大量平行针状α丛互相交错的网篮组织。Effects of triple heat treatments on phase transformation and microstructure of TC21 titanium alloy after superplastic deformation were investigated by superplastic tensile test and optical microscope（ OM） observation. The results show that the cooling rate of first-time heat treatment significantly influences the microstructure of the alloy; and the α phase grows into Widmanstatten structure from β grain by furnace cooling,the large needle shaped martensite plate forms by water cooling,and the α″ phase is precipitated from β grain by air cooling. The cooling rate of second time heat treatment mainly affects the morphology of secondary α phase; and the secondary α phase grows into thinner Widmanstatten structure by furnace cooling,and the basketweave microstructure forms by a large number of parallel acicular α phase plexus,which can only be nucleated from the fine dispersed α″ precipitates by air cooling.

关 键 词：TC21合金 冷却速率 三重热处理 网篮组织 

分 类 号：TG146.2[一般工业技术—材料科学与工程]