Microstructural Development in Tension and Compression Creep of Magnesium Alloy AE42

摘要

Investigations on creep resistant magnesium alloy AE42 were performed in creep tests in compressive and tensile mode. Minimum creep rates and stress exponents n were calculated and compared for tests with the same temperature and load. Linear fits of minimum creep rates in log/log plots at all temperatures shows a similar behavior. The higher the load the bigger is the difference between minimum creep rate at tensile and compression tests. At loads around 40 MPa rates adjust to similar values. During creep microstructural evolution is different. Wide twins form during eompressive creep tests whereas double-directed fine twins with an angle of approximately 51 deg are formed during tensile creep test. The difference in twinning is supposed to be one of the reason for different creep rates.