中文摘要：

在变形温度为823~973K,应变速率为0.01~1s-1的条件下,采用热压缩实验研究了无铅易切削黄铜合金的高温流变应力行为,结果表明：在所有变形条件下该合金的流变曲线均出现软化现象,这种流变软化主要是由于发生了动态再结晶和β→α相变造成的.基于热压缩试验所得实测数据,建立了材料常数为应变的6次多项式函数的双曲正弦形式的本构模型,与实验数据对比表明,该模型能够较好地预测无铅易切削黄铜合金的流变应力.

英文摘要：

The hot deformation behaviors of the newly developed lead-free machinable brass are investigated by isothermal compression tests on a Gleeble-1500thermal-mechanics simulator at temperatures of 823-973Kand strain rates ranging from 0.01 to 1s-1.The typical flow curves exhibit softening at all the deformation conditions,which have been considered that the flow softening results from the occurrence of DRX behavior and theβ→αphase transformation of the lead-free machinable brass.On the basis of the experimental data,a new constitutive model with the material constants expressed by a sixth order polynomial fitting of strain was developed through a hyperbolic-sine Arrhenius type equation to relate the flow stress,strain rate and temperature.The flow stresses calculated by the proposed constitutive model are good agreement with the experimental ones.