Microstructural analysis of fine-grained magnesium after cyclic tension-tension fatigue testing at 0?

Microstructures were characterized for the fine-grained magnesium samples that experienced tension-tension fatigue testing and quasi-static tensile testing at 0 ?. Three fatigue cases were selected based on the relation between the maximum loading stress (sigma max) of fatigue testing and the material's yield strength (sigma y). sigma max was lower than sigma y for the first case, about equal to sigma y for the second case, and higher than sigma y for the third case. No tensile twinning was observed in the tested samples. With the increase of & USigma;max experienced by the material, the number of small grains decreased and the number of large grains increased in the tested samples. Average grain size became larger for the samples after testing, and it increased linearly with the increase of & USigma;max. Grain growth began with the merging of the blocks of small grains and continued with the merging of small grains to the neighboring large grains through grain rotation when & USigma;max was increased.(c) 2022 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).