Strain-controlled low cycle fatigue properties of a rare-earth containing ME20 magnesium alloy

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• 作者：F.A. Mirza^a ; ^{f4mirza@ryerson.ca" class="auth_mail" title="E-mail the corresponding author} ; K. Wang^a ; S.D. Bhole^a ; J. Friedman^a ; D.L. Chen^a ; D.R. Ni^b ; B.L. Xiao^b ; Z.Y. Ma^b ; ^{zyma@imr.ac.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Magnesium alloy ; Rare-earth elements ; Cyclic deformation ; Twinning-detwinning ; Texture weakening
• 刊名：Materials Science & Engineering A
• 出版年：2016
• 出版时间：20 April 2016
• 年：2016
• 卷：661
• 期：Complete
• 页码：115-125
• 全文大小：5402 K

文摘

The present study was aimed to evaluate the strain-controlled cyclic deformation characteristics and low cycle fatigue (LCF) life of a low (~0.3 wt%) Ce-containing ME20-H112 magnesium alloy. The alloy contained equiaxed grains with ellipsoidal particles containing Mg and Ce (Mg₁₂Ce), and exhibited a relatively weak basal texture. Unlike the high rare earth (RE)-containing magnesium alloy, the ME20M-H112 alloy exhibited asymmetrical hysteresis loops somewhat similar to the RE-free extruded Mg alloys due to the presence of twinning-detwinning activities during cyclic deformation. While cyclic stabilization was barely achieved even at the lower strain amplitudes, cyclic softening was the predominant characteristics at most strain amplitudes. The ME20M-H112 alloy showed basically an equivalent fatigue life to that of the RE-free extruded Mg alloys, which could be described by the Coffin-Manson law and Basquin's equation. Fatigue crack was observed to initiate from the near-surface imperfections, and in contrast to the typical fatigue striations, the present alloy showed some shallow dimples along with some fractions of quasi-cleavage features in the crack propagation area.