铝-钨粉末合金涡旋定盘热挤压成形工艺研究

Research on the hot extrusion process of fixed scroll of Al-W alloy powder

试验研究了铝-钨合金粉末的冷压、热压制坯成形工艺,确定主要挤压工艺参数。该合金涡旋定盘挤压件致密度达到99%左右。利用Gleeble-1500热模拟机测试了该合金在变形温度为450℃~540℃,应变速率为（10-3~1）s-1条件下的流变力学行为。采用Fields-Backofen本构模型实现了对该材料应力-应变曲线的拟合。通过引入一个＂软化因子＂,更好地描述了变形温度、应变速率和应变对流变应力的影响,进一步完善了流变应力本构模型。通过有限元模拟对涡旋定盘挤压件成形进行数值模拟,确定合理的挤压成形工艺,并通过试验进行验证,最终获得了合格的涡旋定盘挤压件。

Al-W alloy powder was used to make billets by the process of cold and hot pressing. Main parameters of the extrusion process were determined and the extrusion density of fixed scroll reached about 99%. Based on the Gleeble-1500 thermal mechanical simulation,the rheological behavior of this alloy was tested at（ 10^-3- 1） s^-1 strain rate and 450℃- 540℃ deformation temperature. The Fields-Backofen constitutive material model applied on fitting the stress-strain curve. A ＂softening factor＂was introduced to better describe the influence of deformation temperature,strain rate and strain on the flow stress and further improved the flow stress constitutive model. The numerical simulation of fixed scroll extrusion forming was conducted through the finite element simulation. A reasonable extrusion process was determined and verified through experiment. Finally,the qualified extrusion parts were obtained.