Texture weakening in pure magnesium during grain growth

ABSTRACT

The microstructure and texture evolution during annealing of rolled pure Mg, at temperatures ranging from 150 to 400°C, was characterised in the present study. A grain growth exponent of n = 13 was observed and the activation energy for grain growth kinetics was found to be 95.6 kJ mol⁻¹. Further, broadening of the normalised grain size distributions, indicating abnormal grain growth, was also observed at all temperatures of annealing. The sample had a dominant basal texture before annealing. However, after annealing up to a temperature of 300°C, the alleviation of basal texture was observed in the samples. On further annealing at a temperature of 400°C, a strong basal texture was developed in the samples. The mobility of high angle grain boundaries, which is proportional to correlated misorientation distribution, was observed to be responsible for texture strengthening of the material. The grain boundary mobility changes during grain growth led to the growth of either small or large grains. It was further observed that the growth of small grains caused the formation of basal fibre and large grains led to the weakening of basal texture.

KEYWORDS:

• Magnesium alloys
• annealing
• grain growth
• texture
• grain boundary engineering

Acknowledgement

The authors would like to thank Prof. I. Samajdar, Dept. of Metallurgical Engg. and Materials Science, IIT Bombay for conducting EBSD measurements of the samples.

Disclosure statement

No potential conflict of interest was reported by the authors.