摘要
对空冷态TC11钛合金在温度750~1100℃、应变速率0.001~10.0s^-1范围内进行等温压缩实验,利用流动应力.应变曲线和加工图研究了该合金在α+β两相区和∥单相区的高温流变行为、流变失稳现象及变形机制。结果表明,在α+β两相区,流动应力超过峰值后在低温区随应变的增大持续下降,在中、高温区先下降最后趋于接近稳定的应力值;在β单相区,流动应力随应变的增大略有下降然后逐渐趋于稳定。在加工图上,α+β两相区叩值较高的范围大致为750~900℃、0.001~0.006S0和900~1000℃、0.001~0.02s^-1,分别是口片层的球化起作用和口片层的球化及α+β→β相变同时起作用的区域;β单相区η值较高的区域大致为1000~1100℃、0.003~0.3s^-1,是动态再结晶起作用的区域。这些区域均是良好的加工区域。流变失稳区为750~875℃、0.006~10.0s^-1,875~975℃、0.03~10.0s^-1和975~1100℃、1.0~10.0s^-1,失稳现象表现为宏观剪切、绝热剪切带和β晶粒的不均匀变形。
The isothermal compression tests for air-cooled titanium alloy TC11 were carried out in the temperature range of 750-1100 ℃ and strain rate range of 0.001-10.0 s-1, and the high temperature flow behavior, the flow instability and the deformation mechanism were investigated in α+β phase field and β phase field for this alloy by using flow stress-strain curve and processing map. The results show that in excess of peak stress the flow stress decreases continuously with increasing of strain at low temperatures in α+β phase, but first decreases and then reaches an approximately constant value at moderate and high temperatures in α+β phase; the flow stress decreases slightly and then tends gradually toward a constant value with increasing of stain in phase field. In the processing maps of this alloy, the domains with high value of r/in α+βphase are about (750-900 ℃, 0.001-0.006 s1) and (900-1000℃, 0.001-0.02 s^-1). In these two domains, the spheroidization of a lamellae occurs, and the combination of spheroidization of α lameUae and α+β→β phase transformation happens, respectively. The domain with high value of r/in fl phase field is about (1000-1100 ℃, 0.003-0.3 sl), where dynamic recrystallization undergoes. The above domains are desirably to be selected for hot working. The domains of flow instability are (750-875 ℃, 0.006-10.0 s^-1), (875-975 ℃, 0.03~10.0 s^-1) and (975-1100 ℃, 1.0-10.0 s^-1), and the manifestations of flow instability are macroscopic shear, adiabatic shear band and non-uniform deformation of fl grains.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2014年第2期375-380,共6页
Rare Metal Materials and Engineering
基金
国家自然科学基金(51005112)
江西省教育厅科技项目(GJJ11156)
轻合金加工科学和技术国防重点学科实验室开放基金(GF200901008)
关键词
空冷态TC11钛合金
高温流变行为
加工图
流变失稳
球化
air-cooled titanium alloy TC 11
high temperature flow behavior
processing map
flow instability
spheroidization