(合肥工業(yè)大學(xué) 材料科學(xué)與工程學(xué)院，合肥 230009)
摘 要: 采用OM、XRD和EBSD研究經(jīng)過β相區(qū)加熱，在不同工藝參數(shù)下熱變形水冷淬火后TA15鈦合金的顯微組織、相變和織構(gòu)演化規(guī)律。結(jié)果表明：顯微組織主要由被壓扁、拉長的原始β晶粒轉(zhuǎn)變的α′馬氏體相及清晰β晶界組成，相變點(diǎn)以下溫度變形的顯微組織中出現(xiàn)沿原始β晶界分布的細(xì)小晶界α相晶粒；通過切變方式形成α′馬氏體相固溶了Al和V元素，且晶格點(diǎn)陣收縮，衍射峰向高角度方向偏移；α′馬氏體與原始β的晶體取向間滿足Burgers位向關(guān)系，顯微組織的晶粒取向分布也類似，且隨著變形溫度和應(yīng)變速率的提高，材料的晶粒取向性增強(qiáng)；顯微組織的晶粒尺寸均在7 μm以內(nèi)，α′晶粒繼承母相β晶粒的取向差，在10°、60°和90°附近出現(xiàn)峰值。
關(guān)鍵字: TA15鈦合金；β相區(qū)加熱；熱變形；相變；織構(gòu)；組織演化
（School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, China）
Abstract:The microstructure, phase transition and texture evolution of TA15 titanium alloy after β phase region heating through hot deformation under different process parameters and water quenching were investigated by OM, XRD and EBSD. The results indicate that the microstructure is mainly composed of α′ martensite phase transformed from flatted and elongated β grains and clear β grain boundaries. There are some tiny grain boundary α grains distributed along original β grain boundaries through hot deformation below the phase transition point. Al and V elements were dissolved in α′ martensite phase formed by the shear mode, and resulted in crystal lattice contraction and the diffraction peak moving to high-angle. The grain orientation distributions are similar owing to the crystal orientations between martensite α′ and original β complying with the Burgers orientation relationship. The grain orientations of material are enhanced with increasing temperature and strain rate. The average grain size is less than 7 μm and α′ grains inherit the misorientation of parent β grains when the peaks of the number fraction locate at 10°, 60° and 90°.
Key words: TA15 titanium alloy; β phase region heating institution; hot deformation; phase transition; texture; microstructure evolution
