Characteristics and distribution of microstructures in high pressure die cast alloys with X-ray microtomography: A review

Al and Mg alloy high pressure die castings (HPDC) are increasingly used in automotive industries. The microstructures in the castings have decisive effect on the casting mechanical properties, in which the microstructure characteristics are fundamental for the investigation of the microstructure-property relation. During the past decade, the microstructure characteristics of HPDC Al and Mg alloys, especially micro-pores and α-Fe, have been investigated from two-dimensional (2D) to three-dimensional with X-ray micro-computed tomography (μ-CT). This paper provides an overview of the current understanding regarding the 3D characteristics and formation mechanisms of microstructures in HPDC alloys, their spatial distributions, and the impact on mechanical properties. Additionally, it outlines future research directions for the formation and control of heterogeneous microstructures in HPDC alloys.