In this work, tensile tests were conducted on two powder metallurgy materials based on the AZ31 magnesium alloy. The first material, named AZ31-PM, was processed using atomized powder, followed by isostatic cold compaction at 340 MPa, plus hot extrusion at 350 °C. The second material, named AZ31-PMCM, used metal powder that was cryomilled in liquid nitrogen environment and processed as for the AZ31-PM material. Creep mechanisms were analyzed in the range 300 °C to 400 °C based on the creep laws determined previously for ingot metallurgy AZ31. Two threshold stresses, one for grain boundary sliding and the other for slip creep, both independent of temperature, were introduced, providing a consistent description of creep for the different AZ31-based materials. The variations observed in threshold stresses in the AZ31-PM material were attributed to an inhomogeneous distribution of dispersoids and satisfactorily explained by a composite type model. This method of analyzing the data is compared with the traditional one in the literature, demonstrating that the dependence of the threshold stresses with the temperature, reported in those articles, could actually be derived from the method used rather than from a real physical effect.

在这项工作中，对基于AZ31镁合金的两种粉末冶金材料进行了拉伸测试。使用雾化粉末加工名为AZ31-PM的第一种材料，然后在340 MPa下进行等静压压实，再在350°C下热挤压。第二种材料称为AZ31-PMCM，它使用在液氮环境中进行低温研磨并按照AZ31-PM材料进行处理的金属粉末。根据先前为铸锭冶金AZ31确定的蠕变定律，在300°C至400°C的范围内分析了蠕变机理。引入了两个阈值应力，一个用于晶界滑动，另一个用于滑动蠕变，均与温度无关，从而为不同的AZ31基材料提供了蠕变的一致描述。AZ31-PM材料在阈值应力中观察到的变化归因于弥散体的不均匀分布，并且可以通过复合类型模型令人满意地进行解释。将这种分析数据的方法与文献中的传统方法进行了比较，表明这些文章中报道的阈值应力与温度的相关性实际上可以从所使用的方法中得出，而不是从实际的物理效果中得出。