Evaluating the morphology of precipitates and the room temperature mechanical properties of age hardened AZT802 magnesium alloy treated at different aging temperature

Abstract T6 aging treatment was performed at 423 K and 473 K for AZT802 wrought magnesium alloy. To understand the effects of temperature on the aging behavior and mechanical properties, microstructure and uniaxial tensile performance at room temperature were studied. Aging temperature obviously affected the rate of precipitation. Temperature sensibilities of continuous precipitates and discontinuous precipitates were different and continuous precipitates were far more sensitive phases. With increasing aging temperature, continuous precipitates grew coarsely. Meanwhile, densities of continuous precipitates and part of discontinuous precipitates decreased rapidly. Mechanical properties and fracture analysis indicated that compact second phases reinforced matrix effectively. Cracks extended mainly through zones of discontinuous precipitates in the sample which was aged at 423 K. But when the aging temperature raised to 473 K, the sample tended to fracture mainly along zones of continuous precipitates and coarsely discontinuous precipitates.