Journal of Materials Research and Technology (Jan 2022)

Crack source and propagation of AZ91-0.9Gd alloy

  • Huisheng Cai,
  • Zhenzhu Wang,
  • Liang Liu,
  • Yuguang Li,
  • Fangjing Xing,
  • Feng Guo

Journal volume & issue
Vol. 16
pp. 1571 – 1577

Abstract

Read online

Formation process of main compounds in AZ91-0.9Gd alloy was studied, and main crack sources and fracture mechanism were analyzed. Experimental results show that AZ91-0.9Gd alloy is mainly composed of α-Mg, Mg17Al12, bulk Al2Gd compound and a small amount of Al–Mn-Gd ternary compound. Formation sequence is α-Mg, Al2Gd, Mg17Al12 and Al–Mn-Gd. During load process, Al2Gd and Mg17Al12 compounds are main crack sources and important locations of crack propagation path. The main crack locations include grain boundary, phase boundary, Al2Gd and Mg17Al12 compounds. The continuous network distribution along grain boundaries of Mg17Al12 compound is an important reason for intergranular fracture and poor plasticity of alloy. Fracture mechanism is that with the increase of load, there are many micro cracks occur at Al2Gd and Mg17Al12 in alloy, a micro crack grows rapidly to form main crack, and gradually connects with other micro cracks, so that the main crack becomes larger until alloy fracture failure.

Keywords