TY - JOUR

T1 - Effect of Zn addition on hot tearing behaviour of Mg-0.5Ca-xZn alloys

AU - Song, Jiangfeng

AU - Wang, Zhi

AU - Huang, Yuanding

AU - Srinivasan, Amirthalingam

AU - Beckmann, Felix

AU - Kainer, Karl Ulrich

AU - Hort, Norbert

PY - 2015/12/15

Y1 - 2015/12/15

N2 - The influence of Zn addition (0, 0.5, 1.5, 4.0 and 6.0wt.%) on hot tearing behaviour of Mg-0.5wt.% Ca alloy was investigated using a constrained rod casting (CRC) apparatus. The effects of mould temperature and grain refinement on the hot tearing susceptibility (HTS) were studied. Hot tears were observed with 3D X-ray tomography and the tear volumes were quantified. Results show that the Zn addition increases the HTS of Mg-0.5Ca alloys. At a mould temperature of 250°C, all alloys investigated except Mg-0.5Ca-6Zn alloy show severe HTS. An increase in the mould temperature from 250°C to 450°C did not reduce the HTS in Mg-0.5Ca-1.5Zn and Mg-0.5Ca-4Zn alloys. Among all the investigated alloys, Mg-0.5Ca-4Zn alloy exhibits severe HTS as it completely broke away from the sprue-rod junction. The HTS of alloys was well correlated with the susceptible temperature range (δTs). An increase in δTs increased the HTS. The hot tears propagated along the grain boundaries through liquid film rupture. Grain refinement by Zr addition improved the hot tearing resistance of Mg-0.5Ca-4Zn alloy as the fine grain structure facilitated the easy feeding of liquid into the last area of solidification and accommodated the developed strain more effectively.

AB - The influence of Zn addition (0, 0.5, 1.5, 4.0 and 6.0wt.%) on hot tearing behaviour of Mg-0.5wt.% Ca alloy was investigated using a constrained rod casting (CRC) apparatus. The effects of mould temperature and grain refinement on the hot tearing susceptibility (HTS) were studied. Hot tears were observed with 3D X-ray tomography and the tear volumes were quantified. Results show that the Zn addition increases the HTS of Mg-0.5Ca alloys. At a mould temperature of 250°C, all alloys investigated except Mg-0.5Ca-6Zn alloy show severe HTS. An increase in the mould temperature from 250°C to 450°C did not reduce the HTS in Mg-0.5Ca-1.5Zn and Mg-0.5Ca-4Zn alloys. Among all the investigated alloys, Mg-0.5Ca-4Zn alloy exhibits severe HTS as it completely broke away from the sprue-rod junction. The HTS of alloys was well correlated with the susceptible temperature range (δTs). An increase in δTs increased the HTS. The hot tears propagated along the grain boundaries through liquid film rupture. Grain refinement by Zr addition improved the hot tearing resistance of Mg-0.5Ca-4Zn alloy as the fine grain structure facilitated the easy feeding of liquid into the last area of solidification and accommodated the developed strain more effectively.

KW - 3D X-ray tomography

KW - Grain refinement

KW - Hot tearing

KW - Mg-0.5Ca-xZn alloys

KW - Mould temperature

KW - Engineering

UR - http://www.scopus.com/inward/record.url?scp=84944200186&partnerID=8YFLogxK

U2 - 10.1016/j.matdes.2015.08.026

DO - 10.1016/j.matdes.2015.08.026

M3 - Journal articles

AN - SCOPUS:84944200186

VL - 87

SP - 157

EP - 170

JO - Materials and Design

JF - Materials and Design

SN - 0264-1275

ER -