挤压态HNi55-7-4-2镍黄铜合金的热变形行为和加工图

Hot deformation behavior and processing map of extruded HNi55-7-4-2 nickel-brass alloy

首先,以挤压态HNi55-7-4-2镍黄铜合金为对象,应用热模拟机Gleeble-3500对其进行等温热压缩实验,研究该合金在600~800℃和0.01~10 s^(-1)条件下的热变形行为。其次,基于动态材料模型和极性交互模型,分别建立HNi55-7-4-2镍黄铜合金的Prasad、Murty和PRM加工图,并结合不同变形条件下的微观组织演变,对比3种加工图的预测效果。结果表明:Murty加工图预测效果最差,而Prasad加工图和PRM加工图预测效果较好。HNi55-7-4-2镍黄铜合金的最优热变形加工参数范围为:变形温度为600~725℃,应变速率为0.01~0.07 s^(-1)和变形温度为740~800℃,应变速率为0.05~1 s^(-1)。失稳区的变形机制为局部塑性流动和混晶组织,安全区的变形机制为动态再结晶。

Firstly,the hot deformation behavior of extruded HNi55-7-4-2 nickel-brass alloy under the conditions of deformation temperature of 600-800℃ and strain rate of 0.01-10 s-1was studied by isothermal compression experiment with Gleeble-3500 thermal simulator.Secondly,based on the dynamic material model and polar reciprocity model,Prasad,Murty and PRM processing maps of the HNi55-7-4-2 nickel-brass alloy were established respectively,and the prediction effects of the three processing maps were compared in combination with the microstructure evolution under different deformation conditions.The results show that the Murty processing map has the worst prediction effect,while Prasad processing map and PRM processing map have better prediction effect.The range of the optimal hot deformation processing parameters of the HNi55-7-4-2 nickel-brass alloy is as follows:the deformation temperature of 600-725℃ and the strain rate of 0.01-0.07 s^(-1),and the deformation temperature of 740-800℃ and the strain rate of 0.05-1 s^(-1).The deformation mechanism of the instability zone is local plastic deformation and mixed-grain microstructure,while that of the stable zone is dynamic recrystallization.