Hot crack susceptibility of cast Mg₉₇Y₂Zn₁

Abstract

Formation of hot cracks in alloys is a critical issue for their production and processing. In this study, the susceptibility of the cast Mg97Y2Zn1 alloy containing long period stacking ordered (LPSO) structures to hot cracking was investigated using tensile tests in a Gleeble testing machine, and described in terms of the brittle temperature range (BTR), which was concluded from the zero strength temperature (ZST), zero ductility temperature, and ductility recovery temperature (DRT). The zero ductility and the DRTs were obtained directly from the mechanical tests, verified using fracture surface analysis in a scanning electron microscope, and correlated with the solidification range that was determined using differential scanning calorimetry. The extent of the BTR was 31 K, the width of the solidification range 100 K. The ZST coincided with the dissolution temperature of the LPSO structures, which means that the hot cracking susceptibility of the cast Mg97Y2Zn1 alloy is dominated by the dissolution of LPSO structures.