(1. 南昌航空大學(xué) 輕合金加工科學(xué)與技術(shù)國防重點(diǎn)學(xué)科實(shí)驗(yàn)室，南昌 330036；
2. 航空工業(yè)西安飛機(jī)工業(yè)(集團(tuán))有限責(zé)任公司，西安 710089)
摘 要: 利用等溫壓縮實(shí)驗(yàn)研究了β轉(zhuǎn)變組織TA15鈦合金在變形溫度750~950 ℃、應(yīng)變速率0.001~10 s-1范圍內(nèi)的流動(dòng)軟化行為，定量分析了變形熱效應(yīng)和微觀組織演變對流動(dòng)軟化行為的影響。結(jié)果表明：變形熱效應(yīng)是β轉(zhuǎn)變組織TA15鈦合金流動(dòng)軟化的重要機(jī)制，變形熱軟化程度隨著變形溫度的下降和應(yīng)變速率的增大而增強(qiáng)，最高占到總流動(dòng)軟化程度的48.2%；動(dòng)態(tài)再結(jié)晶、動(dòng)態(tài)回復(fù)和流動(dòng)失穩(wěn)缺陷等形式的微觀組織演變是流動(dòng)軟化的主要機(jī)制。基于動(dòng)態(tài)材料模型，利用應(yīng)變速率敏感性指數(shù)預(yù)測了3種微觀組織演化形式主導(dǎo)的軟化區(qū)域，并通過微觀組織觀測進(jìn)行了驗(yàn)證。
關(guān)鍵字: TA15鈦合金；流動(dòng)軟化；變形熱效應(yīng)；微觀組織演變
（1. National Defense Key Disciplines Laboratory of Light Alloy Processing Science and Technology, Nanchang Hangkong University, Nanchang 330063, China;
2. Aviation Xi’an Aircraft Industry Croup Co., Ltd., Xi’an 710089, China）
Abstract:The flow softening of TA15 titanium alloy with beta transformed microstructure was investigated by means of hot compression tests performed at the temperature range of 750-950 ℃ and strain rate of 0.001-10 s-1. The effect of deformation temperature and strain rate on the flow softening and the flow softening mechanisms were examined. The thermal softening due to deformation heating is an important mechanism of flow softening. The degree of thermal softening increases with the decrease of deformation temperature and the increase of strain rate, and the maximum is 48.2% to the total flow softening degree. The microstructural evolution, including dynamic recrystallization, dynamic recovery and flow instability defects, is the main mechanism of flow softening. Three types of softening regions dominated by microstructure evolution were identified by strain rate sensitivity index based on the dynamic material model, and verified by microstructure observation.
Key words: TA15 titanium alloy; flow softening; deformation heating; microstructural evolution
