(1. 中南大學(xué) 粉末冶金國家重點(diǎn)實(shí)驗(yàn)室，長沙 410083；2. 中南大學(xué) 冶金科學(xué)與工程學(xué)院，長沙 410083；
3. 湖南金天鈦業(yè)科技有限公司，常德 410007)
摘 要: 在Gleeble-1500 熱模擬機(jī)上對Ti-5Al-5Mo-5V-1Cr-1Fe合金進(jìn)行高溫?zé)釅嚎s實(shí)驗(yàn)，研究該合金在變形溫度為750~900 ℃、應(yīng)變速率為0.001~1 s−1 條件下的流變應(yīng)力行為。利用光學(xué)顯微鏡分析合金在不同變形條件下的組織演化規(guī)律。結(jié)果表明：合金的流變應(yīng)力隨著應(yīng)變速率的增大和變形溫度的降低而增大；流變應(yīng)力隨著應(yīng)變的增加而增大，出現(xiàn)峰值后逐漸趨于平穩(wěn)；變形過程中的流變應(yīng)力可用Arrhenius雙曲正弦本構(gòu)關(guān)系來描述，平均變形激活能為454.2 kJ/mol；各種變形條件均可細(xì)化原始晶粒尺寸。隨著溫度的升高和應(yīng)變速率的降低，合金的主要軟化機(jī)制由動(dòng)態(tài)回復(fù)逐漸變?yōu)閯?dòng)態(tài)再結(jié)晶；在(α+β)相區(qū)變形(750~850 ℃)時(shí)，α相對β晶粒的動(dòng)態(tài)再結(jié)晶的發(fā)生起到阻礙作用。
關(guān)鍵字: Ti-5Al-5Mo-5V-1Cr-1Fe合金；熱變形；流變應(yīng)力；顯微組織
（1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. School of Metallurgical Science and Engineering, Central South University, Changsha 410083, China;
3. Hunan Goldsky Titanium Industry Technology Co. Ltd., Changde 410007, China）
Abstract:The hot deformation behaviors of Ti-5Al-5Mo-5V-1Cr-1Fe alloy were studied by a Gleeble-1500 machine at 750−900 ℃ with the strain rate of 0.001−1 s−1. The microstructural evolution of the alloy was investigated by optical microscopy. The results indicate that the flow stress of the alloy increases with increasing strain rate and decreasing deformation temperature. The flow stress increases with increasing strain until the stress reaches the peak value, then the flow stress remains constant. The flow stress in deformation can be described by Arrhenius hyperbolic sine constitutive equation, and the average activation energy is 454.2 kJ/mol. The original grain size can be refined under all deformation conditions. The main softening mechanism is changed from dynamic recovery to dynamic recrystallization with increasing the deformation temperature and decreasing the strain rate. In the (α+β) region (750−850 ℃), α phase can inhibit the dynamic recrystallization of β grains particles during deformation.
Key words: Ti-5Al-5Mo-5V-1Cr-1Fe alloy; hot deformation; flow stress; microstructure
