亚稳β钛合金Ti-1500热变形行为  

Hot deformation behavior of metastableβ-titanium alloy Ti-1500

作　　者：张书铭 林博超 辛社伟[2] 王钧仡 黄志涛 付明杰 Zhang Shuming;Lin Bochao;Xin Shewei;Wang Junyi;Huang Zhitao;Fu Mingjie(AVIC Manufacturing Technology Institute,Beijing 100024,China;Northwest Institute for Nonferrous Metal Research,Xi'an Shaanxi 710016,China)

机构地区：[1]中国航空制造技术研究院,北京100024 [2]西北有色金属研究院,陕西西安710016

出　　处：《金属热处理》2023年第5期158-165,共8页Heat Treatment of Metals

摘　　要：通过等温热压缩试验研究了新型亚稳β钛合金Ti-1500在750~910℃、0.001~10 s^(-1)条件下的热变形行为。建立了耦合应变的双曲正弦型Arrhenius本构方程,基于动态材料模型及Prasad流变失稳准则构建了热加工图,分析了变形后的显微组织。结果表明,随着变形温度升高、应变速率降低,合金的流变应力降低,相同条件下合金的峰值流变应力略高于Ti55531合金,低于M28合金。合金在两相区的平均热变形激活能为291.36 kJ/mol,远高于纯钛的自扩散激活能,β单相区为153.96 kJ/mol,与纯钛的自扩散激活能接近。两相区能量耗散效率峰值位于低应变速率(0.001 s^(-1));单相区能量耗散效率峰值位于中低应变速率(0.01~0.1 s^(-1));所有试验温度下,应变速率高于1 s^(-1)时发生变形失稳。结合显微组织分析可以将变形分为3个区域,即低温低应变速率下的β→α相变区、中高温低应变速率下的β再结晶区以及高应变速率下变形不均匀的失稳区。The hot deformation behaviors of a new type of metastableβ-titanium alloy Ti-1500 were studied through isothermal compression tests at 750-910℃with 0.001-10 s^(-1).The hyperbolic sine Arrhenius constitutive equation of coupled strain was established.Based on the dynamic material model and Prasad's rheological instability criterion,the hot working diagrams were constructed,and the microstructure after deformation was analyzed.The results show that the flow stress of the alloy decreases as the deformation temperature increases and the strain rate decreases.Under the same conditions,the peak flow stress of the alloy is slightly higher than that of the Ti55531 alloy,but lower than that of the M28 alloy.The average thermal deformation activation energy of the alloy in the two-phase region is 291.36 kJ/mol,which is much higher than the self-diffusion activation energy of pure titanium.The activation energy in theβsingle-phase region is 153.96 kJ/mol,which is close to the self-diffusion activation energy of pure titanium.The peak value of energy dissipation efficiency in the two-phase region is located at a low strain rate(0.001 s^(-1)),while the peak value of energy dissipation efficiency in the single-phase region lies in the middle and low strain rates(0.01-0.1 s^(-1)).At all test temperatures,deformation instability occurs when the strain rate is higher than 1 s^(-1).Combined with microstructure analysis,deformation can be divided into three regions,namely low temperature and low strain rateβ→αphase transition zone,medium to high temperature and low strain rateβrecrystallization zone and unstable region with uneven deformation at high strain rates.

关 键 词：Ti-1500亚稳β钛合金 热变形 本构方程 热加工图 动态回复 不连续动态再结晶 

分 类 号：TG115.6[金属学及工艺—物理冶金]