Hot isostatic pressing parameters are critical to Ti60 high temperature titanium alloy castings which have wide application perspective in aerospace.In order to obtain optimal processing parameters,the effects of hot ...Hot isostatic pressing parameters are critical to Ti60 high temperature titanium alloy castings which have wide application perspective in aerospace.In order to obtain optimal processing parameters,the effects of hot isostatic pressing parameters on defects,composition uniformity,microstructure and mechanical properties of Ti60 cast high temperature titanium alloy were investigated in detail.Results show that increasing temperature and pressure of hot isostatic pressing can reduce defects,especially,the internal defects are substantially eliminated when the temperature exceeds 920℃or the pressure exceeds 125 MPa.The higher temperature and pressure can improve the microstructure uniformity.Besides,the higher pressure can promote the composition uniformity.With the temperature increases from 880℃to 960℃,α-laths are coarsened.But with increasing pressure,the grain size of prior-βphase,the widths ofα-laths andα-colony are reduced.The tensile strength of Ti60 alloy is 949 MPa,yield strength is 827 MPa,and the elongation is 11%when the hot isostatic pressing parameters are 960℃/125 MPa/2 h,which exhibits the best match between the strength and plasticity.展开更多
采用Gleeble-3800热模拟试验机对Ti60钛合金进行了热压缩实验,研究该合金在变形温度800~1150℃和应变速率0.001~1 s^(-1)区间内的热变形行为。结果表明:变形温度和应变速率是决定Ti60钛合金流变应力大小的主要因素,随变形温度升高,应变...采用Gleeble-3800热模拟试验机对Ti60钛合金进行了热压缩实验,研究该合金在变形温度800~1150℃和应变速率0.001~1 s^(-1)区间内的热变形行为。结果表明:变形温度和应变速率是决定Ti60钛合金流变应力大小的主要因素,随变形温度升高,应变速率降低,流变应力减小,表现出较强的温度敏感性和应变速率敏感性;随应变增大,合金的流变应力达到最大值,之后趋于平稳,呈现出流变软化特征。采用双曲正弦模型确定合金在800~900℃、950~1020℃和1050~1150℃的变形激活能分别为545.82、732.78和116.19 k J·mol^(-1),进而建立了合金在不同温度区间变形的本构方程,为制定和优化最佳形变加工工艺提供了理论依据。展开更多
基金supported by the National Natural Science Foundation of China(No.52165050)the Natural Science Foundation of Jiangxi Province,China(No.20181BAB206027).
基金financially supported by the National Key Research and Development Program of China(Grant No.2020YFB2008300)。
文摘Hot isostatic pressing parameters are critical to Ti60 high temperature titanium alloy castings which have wide application perspective in aerospace.In order to obtain optimal processing parameters,the effects of hot isostatic pressing parameters on defects,composition uniformity,microstructure and mechanical properties of Ti60 cast high temperature titanium alloy were investigated in detail.Results show that increasing temperature and pressure of hot isostatic pressing can reduce defects,especially,the internal defects are substantially eliminated when the temperature exceeds 920℃or the pressure exceeds 125 MPa.The higher temperature and pressure can improve the microstructure uniformity.Besides,the higher pressure can promote the composition uniformity.With the temperature increases from 880℃to 960℃,α-laths are coarsened.But with increasing pressure,the grain size of prior-βphase,the widths ofα-laths andα-colony are reduced.The tensile strength of Ti60 alloy is 949 MPa,yield strength is 827 MPa,and the elongation is 11%when the hot isostatic pressing parameters are 960℃/125 MPa/2 h,which exhibits the best match between the strength and plasticity.
文摘采用Gleeble-3800热模拟试验机对Ti60钛合金进行了热压缩实验,研究该合金在变形温度800~1150℃和应变速率0.001~1 s^(-1)区间内的热变形行为。结果表明:变形温度和应变速率是决定Ti60钛合金流变应力大小的主要因素,随变形温度升高,应变速率降低,流变应力减小,表现出较强的温度敏感性和应变速率敏感性;随应变增大,合金的流变应力达到最大值,之后趋于平稳,呈现出流变软化特征。采用双曲正弦模型确定合金在800~900℃、950~1020℃和1050~1150℃的变形激活能分别为545.82、732.78和116.19 k J·mol^(-1),进而建立了合金在不同温度区间变形的本构方程,为制定和优化最佳形变加工工艺提供了理论依据。
