【摘要】 利用Gleeble1500热/力模拟机对Ti14合金进行了半固态压缩变形试验,研究了该合金在应变速率为5×10-2s-1和5×10-1s-1,变形温度为1273~1423K条件下的流变应力变化规律,分析了该合金半固态下应力松弛发生的条件和原因,并讨论了温度、应变速率和变形机制之间的耦合关系。结果表明:温度和应变速率对流变应力有显著的影响,流变应力随着变形温度的升高和应变速率的降低而降低,宏观应力松弛发生在固相含量区间为0.95~0.98,主要是因为液相的增加减少了晶粒间的"固相桥"作用。由于液相在变形中的渗漏,Ti14合金在1273~1423K半固态变形的应变速率试验值远远小于Iwasaki润滑流动机制(固液混合变形机制)所需的理论值,说明在所测试的半固态区间内合金仍以固相粒子变形为主,固液混合变形为协调机制。更多还原

【Abstract】 The semi-solid deformation behavior of Ti14 alloy was investigated by Gleedle1500 at strain rate of 0.05 s-1 and 0.5 s-1 , and the deformation temperature 1273～1423 K. The results show that the strain rate and deformation temperature have strong effects on the flow stress. The maximum compressive stress was greatly depended on fraction solid, and a stress relaxation occurred between 0.95 and 0.98 (the temperature from 1323 K to 1373 K), which was related to the decrease in amount of solid bridges between grains. Because of the partial solid/liquid segregation during deformation, the experimental strain rates are much lower than those calculated by the flow of liquid incorporating solid particles (FLS), which suggested that the main deformation mechanism between 1323 K and 1373 K is still plastic deformation of solid particles (PDS).更多还原