Influences Of Hot-Isostatic-Pressing Temperature On The Microstructure, Tensile Properties And Tensile Fracture Mode Of 2A12 Powder Compact
Published 2016 · Materials Science
Abstract2A12 aluminum alloy powders were hot-isostatic-pressed (HIPed) at representative temperatures for investigating the variation in microstructure, tensile property and fracture mode of the powder compact. It was found that the microstructure of raw powders changed from a dendrite structure to an equiaxed structure from room temperature to 600 °C. The liquid phase produced by the eutectic reaction in the powder was gradually increased and finally formed a liquid pathway that ran through the entire powder from 490 to 600 °C. Prior particle boundaries were observed in the powder compacts HIPed at 490 and 520 °C. The liquid phase in the powder compacts was squeezed into the powder boundaries and the triple points of powder when HIPed at 580 °C. However, the liquid phase located at the triple points of the powder was forced out and moved toward a small powder particle by HIP pressure under an HIPing temperature of 600 °C, which led to a decrease in the mechanical properties and relative density. Better comprehensive properties were obtained at HIPing temperatures of 490 and 580 °C. The low ductility exhibited by the P/M aluminum alloy HIPed at different temperatures was believed to arise from a combination of the existence of oxide film on the powder particle surface and the distribution characteristics of the liquid phase. Finally, three typical types of de-cohesion were classified.