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

Research output: Journal contributionsJournal articlesResearchpeer-review

Authors

  • Jiangfeng Song
  • Zhi Wang
  • Yuanding Huang
  • Amirthalingam Srinivasan
  • Felix Beckmann
  • Karl Ulrich Kainer
  • Norbert Hort

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.

Original languageEnglish
JournalMaterials and Design
Volume87
Pages (from-to)157-170
Number of pages14
ISSN0264-1275
DOIs
Publication statusPublished - 15.12.2015
Externally publishedYes

    Research areas

  • 3D X-ray tomography, Grain refinement, Hot tearing, Mg-0.5Ca-xZn alloys, Mould temperature
  • Engineering