Mechanical and Corrosion Properties of AZ31 Mg Alloy Processed by Equal-Channel Angular Pressing and Aging
Mechanical and Corrosion Properties of AZ31 Mg Alloy Processed by Equal-Channel Angular Pressing and Aging
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DOI：
10.1016/j.proeng.2017.04.113
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
I. Shahar;Taito Hosaka;S. Yoshihara;B. MacDonald
中科院分区：
文献类型：
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作者：
I. Shahar;Taito Hosaka;S. Yoshihara;B. MacDonald
镁（Mg）具有良好的生物相容性，是医用植入物的潜在候选材料。然而，镁合金的主要缺点是腐蚀速度快，特别是在生理pH值为7.4的环境中，因此在组织有足够的时间愈合之前就失去了机械完整性。尽管如此，镁合金作为生物可降解植入物的应用前景广阔，但其耐腐蚀性有待提高。等径角挤压（ECAP）工艺对镁合金的力学性能有显著影响，但随着合金抗拉强度的升高，合金的腐蚀性能反而变差。此外，二次相影响镁铝基合金的耐蚀性。第二阶段起着双重作用，取决于这一阶段的数量和分布。因此，在本研究中，我们试图通过改变ECAP工艺条件和随后的时效来研究晶粒细化和第二相再分配对AZ31镁合金腐蚀行为和力学性能的影响。光学显微组织观察表明，细小而均匀的第二相组织是较好的抗腐蚀屏障，从而提高了合金的耐腐蚀性。
Magnesium (Mg) has a good biocompatibility and thus a potential candidate for medical implants. However, the major drawback of Mg alloys consists of their fast corrosion rate, especially in the physiological pH 7.4environment thereby losing their mechanical integrity before the tissues have sufficient time to heal. Nevertheless, the use of Mg alloys as biodegradable implants has been promising, however their corrosion resistance should be enhanced. It has been known that equal-channel angular pressing (ECAP) process significantly affects the mechanical properties of Mg alloys but as the tensile strength rises, the corrosion performance deteriorates. Additionally, the secondary phase influences the corrosion resistance of magnesium-aluminum based alloys. The second-phase plays dual roles that depend on the amount and distribution of this phase. Therefore, in this study, we attempted to investigate the effect of grain refinement and second-phase redistribution on corrosion behavior and mechanical properties of AZ31 Mg alloy by changing the condition of ECAP process and subsequent aging. Per the optical microstructure observation, a fine and homogeneous second-phase microstructure appears to be a better anti-corrosion barrier, hence enhances the corrosion resistance of the alloy.