(1. 西安交通大学 金属材料强度国家重点实验室，西安 710049；
2. 西北有色金属研究院，西安 710016)
摘 要: 研究了具有片层α组织TC21钛合金在β和α+β相区热轧制后的组织演变规律及其片层组织的球化机制。结果表明：变形温度及应变对具有片层α组织的TC21钛合金断裂及球化具有显著影响。当变形温度为990℃时，在β相区发生变形；当应变不小于0.51时，平行轧向和晶界附近的片层α组织首先发生断裂、球化，晶内片层α组织被压弯变形；当在接近相变点(即950 ℃)变形，应变达到0.92时，片层α组织发生球化；当在两相区较低温度，即910 ℃和870 ℃变形时，片层α取向杂乱，且被压弯成“手风琴”状，未发现球化。TEM观察分析发现，具有α片层组织的TC21钛合金球化过程是一个复杂过程，首先，通过动态回复或是晶界滑移使得α片层中形成α/α界面；然后，β相通过亚晶界楔入α片层，α片层解体；最后，通过物质末端迁移，发生球化。
关键字: TC21钛合金；板材；热轧；组织演变；球化机制
TC21 titanium alloy plate
（1. State Key Laboratory for Mechanical Behavior of Material, Xi’an Jiaotong University，Xi’an 710049, China;
2. Northwest Institute for Nonferrous Metal Research, Xi’an 710016, China）
Abstract:The microstructure evolution and mechanisms of globularization of TC21 titanium alloy with lamellar structure were investigated during hot rolling in the β phase and α+β phase. The results show that the prominent effect of hot working parameters on the break-up and globularization of TC21 titanium alloy with lamellar structure is found. The α lamellar structure along the paralleling rolling orientation and adjacent grain boundaries is broken up and globularized and the intragranular α lamellar is buckled and kinked when TC21 titanium alloy is processed in β phase region (990℃) at strain no less than 0.51 and at 950 ℃ and strain 0.92. When TC21 titanium alloy is deformed at 910 ℃ and 870 ℃, α lamellar is buckled and kinked to become accordion. Then, by TEM analysis, it is found that the mechanism of globularization of TC21 titanium alloy with α lamellar is a comprehensive process that is firstly the formation of α/α interface by dynamic recovery or boundary splitting, secondly the disintegrating of α lamellar due to diffusing, and finally the globularization of α lamellar by termination migration.
Key words: TC21titanium alloys; plate; hot-rolling; microstructure evolution; globularization mechanism
