Influence of microstructure and porosity on the fracture toughness of Al-Si-Mg alloy

摘要

With improving molten metal quality and foundry technology, cast alloys are expected to be used more commonly in critical applications. The demands for improved damage tolerance of cast aluminum alloys have increased the importance of fracture-related properties. In this perspective, the present study aims to evaluate the effect of four different aging treatments on fracture toughness of a die cast A356 Al alloy with and without Cu addition. Crack growth resistance curves (J-R curves) were experimentally evaluated using the ASTM E1820-17 standard procedure on 25 mm thick compact tension C(T) specimens. The influence of microstructure and porosity in hardness and fracture toughness (JIc) is discussed. In addition, microstructural observations were carried out to endorse the fracture mechanisms.