Impression creep behavior of a cast MRI153 magnesium alloy

Abstract Creep behavior of a cast MRI153 magnesium alloy was investigated using impression creep technique. The tests were carried out under constant punching stress in the range of 360–600 MPa at temperatures between 425 and 490 K. Microstructure of the alloy was composed of α(Mg) matrix phase besides Mg 17 Al 12 and Al 2 Ca intermetallic compounds. Stress exponent of minimum creep rate, n, was found to vary between 6.45 and 7. Calculation of the activation energy showed a slight decrease with increasing stress such that the creep activation energy of 115.2 kJ/mol under σ imp / G  = 0.030 decreased to 99.5 kJ/mol under σ imp / G  = 0.040. The obtained stress exponent and activation energy data suggested that the pipe diffusion dislocation climb controlled creep as the dominant mechanism during the creep test.