Preciado Mónica, Bravo Pedro M, Calaf José, Ballorca Daniel
Escuela Politécnica Superior, University of Burgos, 09006 Burgos, Spain.
Materials (Basel). 2019 Mar 15;12(6):872. doi: 10.3390/ma12060872.
During creep, magnesium alloys undergo microstructural changes due to temperature and stress. These alterations are associated with the evolution of the present phases at a microstructural level, creating different strain rates during primary and tertiary creep, and with the stability of the inter-metallic phase MgAl formed at these temperatures. In this paper, the results of creep testing of high-pressure die-cast AZ91 magnesium alloys are reported. During creep, continuous and discontinuous precipitates grow, which influences creep resistance. The creep mechanism that acts at these intermediate temperatures up to 150 °C is termed dislocation climbing. Finally, the influence of the type of precipitates on the creep behavior of alloys is determined by promoting the formation of continuous precipitates by a short heat treatment prior to creep testing.
在蠕变过程中，镁合金会因温度和应力而发生微观结构变化。这些变化与微观结构层面现有相的演变有关，在一次蠕变和三次蠕变过程中产生不同的应变速率，并且与在这些温度下形成的金属间相MgAl的稳定性有关。本文报道了高压压铸AZ91镁合金的蠕变试验结果。在蠕变过程中，连续和不连续析出物会生长，这会影响抗蠕变性。在高达150°C的这些中间温度下起作用的蠕变机制称为位错攀移。最后，通过在蠕变试验前进行短时间热处理促进连续析出物的形成，来确定析出物类型对合金蠕变行为的影响。
