Study on microstructure of squeeze casting AZ91D alloy

Abstract

The present paper reports the investigation of the microstructure distribution of squeeze cast AZ91D alloy. The microstructure of squeeze cast AZ91D alloy is not uniform and is composed of four zones, which are chilled layer, segregation zone, pressured crystallisation area and hot spot area respectively. Moreover, in the pressured crystallisation area, the microstructure sequence in the transverse section from the outside to the inside could be divided into four sublayers, such as fine equiaxial dendrite area, dendrite area with a high directivity, confusion dendrite area and disorder dendrite area. The volume fraction of the intermetallic compound Mg17Al12 also varied with the location. The volume fraction of Mg17Al12 in the pressured crystallisation area is the largest except in the segregated zone.

Phase-field modelling on effect of pressure on growth kinetics of Mg–Al–Sn alloy

“…It is reported that Mg-Al-Sn magnesium alloy is attractive with better combinations of strength and ductility compared with conventional AZ91 or AM50 alloys [1][2][3]. Squeeze casting is an advanced near-net-shape materials processing technology where casting solidifies under applied pressure, which is an essential thermodynamic parameter that determines the microstructure, and thus mechanical properties [1,[4][5][6][7][8][9][10][11][12][13], as seen in squeeze cast AZ91 [4,10] and AM50 [1] alloys.…”