(1. 西安交通大學(xué) 金屬材料強(qiáng)度國家重點(diǎn)實(shí)驗(yàn)室，西安 710049；
2. 西北有色金屬研究院，西安 710016)
摘 要: 研究了具有片層α組織TC21鈦合金在β和α+β相區(qū)熱軋制后的組織演變規(guī)律及其片層組織的球化機(jī)制。結(jié)果表明：變形溫度及應(yīng)變對具有片層α組織的TC21鈦合金斷裂及球化具有顯著影響。當(dāng)變形溫度為990℃時，在β相區(qū)發(fā)生變形；當(dāng)應(yīng)變不小于0.51時，平行軋向和晶界附近的片層α組織首先發(fā)生斷裂、球化，晶內(nèi)片層α組織被壓彎變形；當(dāng)在接近相變點(diǎn)(即950 ℃)變形，應(yīng)變達(dá)到0.92時，片層α組織發(fā)生球化；當(dāng)在兩相區(qū)較低溫度，即910 ℃和870 ℃變形時，片層α取向雜亂，且被壓彎成“手風(fēng)琴”狀，未發(fā)現(xiàn)球化。TEM觀察分析發(fā)現(xiàn)，具有α片層組織的TC21鈦合金球化過程是一個復(fù)雜過程，首先，通過動態(tài)回復(fù)或是晶界滑移使得α片層中形成α/α界面；然后，β相通過亞晶界楔入α片層，α片層解體；最后，通過物質(zhì)末端遷移，發(fā)生球化。
關(guān)鍵字: TC21鈦合金；板材；熱軋；組織演變；球化機(jī)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
