SP700钛合金热变形行为及组织演变  

Hot deformation behavior and microstructure evolution of SP700 titanium alloy

作　　者：田宁 宋晓云 叶文君 惠松骁 TIAN Ning;SONG Xiaoyun;YE Wenjun;HUI Songxiao(State Key Laboratory of Nonferrous Metals and Processes,China GRINM Group Co.,Ltd.,Beijing 100088,China;GRIMAT Engineering Institute Co.,Ltd.,Beijing 101407,China;General Research Institute for Nonferrous Metals,Beijing 100088,China)

机构地区：[1]中国有研科技集团有限公司有色金属材料制备加工国家重点实验室,北京100088 [2]有研工程技术研究院有限公司,北京101407 [3]北京有色金属研究总院,北京100088

出　　处：《工程科学学报》2024年第4期676-683,共8页Chinese Journal of Engineering

基　　金：国家自然科学基金资助项目(51571036)。

摘　　要：采用Gleeble3800热模拟试验机对SP700钛合金进行热压缩试验,研究合金在变形温度为800~880℃、应变速率为1~10 s–1、压缩变形量为30%和50%条件下的流变行为及显微组织演变.结果表明,随着变形温度升高和应变速率降低,SP700钛合金热压缩变形的峰值流变应力降低.合金在800℃压缩变形时,流变应力曲线呈明显的动态软化,其显微组织中α片层逐渐破碎球化,部分α片层发生动态再结晶.随变形温度升高,合金压缩真应力–应变曲线呈稳态流变状态.在相同变形温度下,随应变速率和压缩变形量增加,α片层球化程度增加.热变形过程中,平行于压缩轴的α片层在压应力作用下弯曲扭折,片层内取向差不连续存在,并于不连续处存在新α/α界面.垂直于压缩轴的α片层在压应力作用下界面发生起伏,片层内部存在累积取向差.在界面起伏处β相楔入α片层,最终导致α片层的破碎球化.The hot compression test of SP700 titanium alloy was performed using a Gleeble3800 thermal simulation test machine,and the thermal deformation behavior and microstructure evolution were examined in the temperature range of 800–880°C,strain rate range of 1–10 s-1,and compression deformation of 30%–50%.The findings reveal that the peak flow stress of the SP700 titanium alloy decreases with increasing deformation temperature but increases with increasing strain rate.At a deformation temperature of 800℃,the flow stress curves demonstrate evident dynamic softening features with a rapid decrease in flow stress after the peak stress.By metallographic and scanning electron microstructure observations of the deformed microstructure,theαlamellar is gradually broken and spheroidized,and dynamic recrystallization occurs.With increasing deformation temperature,the induced phase transformation occurs,which leads to the dissolution of theαphase and an increase in the volume fraction of theβphase.The degree of recrystallization of theβphase increases with severalβrecrystallization grains at the grain boundaries,whereas the degree of globularization of theαlamellae decreases with increasing temperature.As the deformation temperature increases to 880℃,the flow stress curves exhibit steady flow.Recrystallization behavior preferentially occurs in theβgrains,while theαlamellar remains flat without globularization behavior.That is,recrystallization of theβphase occurs under the test deformation conditions.For theαlamellae,when the deformation temperature is constant,the degree of spheroidization of theαlamellae increases with strain rate and compression deformation.During the hot deformation process,theαlamellae parallel to the compression axis kink,and the cumulative misorientation is discontinuous inside theαlamellae.At the discontinuous points,the newα/αinterface boundary is produced,which causes the formation of unstable dihedral angles.To lower the surface tension energy,theβphase wedges into theαlamel

关 键 词：SP700钛合金 热变形条件 动态再结晶 高温流动行为 α片层球化 

分 类 号：TG146.2+3[一般工业技术—材料科学与工程]