Corrosion fatigue behaviors of two biomedical Mg alloys-AZ91D and WE43-In simulated body fluid
Corrosion fatigue behaviors of two biomedical Mg alloys-AZ91D and WE43-In simulated body fluid
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DOI：
10.1016/j.actbio.2010.07.026
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发表时间：
2010-12-01
影响因子：
9.7
通讯作者：
Chen, L. J.
中科院分区：
文献类型：
--
作者：
Gu, X. N.;Zhou, W. R.;Chen, L. J.
镁合金是近年来发展起来的可生物降解的植入材料，但对其在循环载荷下的腐蚀疲劳性能的研究尚未见报道。本文选用压铸态AZ91D（A为9%Al，Z为1%Zn，D为第四相）和挤压态WE43（W为4%Y，E为3%RE）合金，研究了它们在模拟体液（SBF）中的疲劳和腐蚀疲劳行为。压铸AZ91D合金在空气中10（7）次循环时的疲劳极限为50 MPa，相比之下，在37 ℃下在SBF中测试的10（6）次循环时的疲劳极限为20 MPa。观察到挤压WE43合金在空气中10（7）次循环的疲劳极限为110 MPa，而在37 ℃的SBF中测试的10（7）次循环的疲劳极限为40 MPa。在空气中和模拟体液中，疲劳裂纹分别从微孔和腐蚀坑中萌生。与压铸AZ91D的脆性断裂模式相比，挤压WE43合金的过载区表现出具有深韧窝的韧性断裂模式。与静态浸泡试验相比，两种实验合金在循环载荷下的腐蚀速率均有所增加。(C)2010 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
Magnesium alloys have been recently developed as biodegradable implant materials, yet there has been no study concerning their corrosion fatigue properties under cyclic loading. In this study the die-cast AZ91D (A for aluminum 9%, Z for zinc 1% and D for a fourth phase) and extruded WE43 (W for yttrium 4%, E for rare earth mischmetal 3%) alloys were chosen to evaluate their fatigue and corrosion fatigue behaviors in simulated body fluid (SBF). The die-cast AZ91D alloy indicated a fatigue limit of 50 MPa at 10(7) cycles in air compared to 20 MPa at 10(6) cycles tested in SBF at 37 degrees C. A fatigue limit of 110 MPa at 10(7) cycles in air was observed for extruded WE43 alloy compared to 40 MPa at 10(7) cycles tested in SBF at 37 degrees C. The fatigue cracks initiated from the micropores when tested in air and from corrosion pits when tested in SBF, respectively. The overload zone of the extruded WE43 alloy exhibited a ductile fracture mode with deep dimples, in comparison to a brittle fracture mode for the die-cast AZ91D. The corrosion rate of the two experimental alloys increased under cyclic loading compared to that in the static immersion test. (C) 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.