The influences of extrusion and equal channel angular pressing (ECAP) processes on the fatigue behavior of AM60 magnesium alloy
The influences of extrusion and equal channel angular pressing (ECAP) processes on the fatigue behavior of AM60 magnesium alloy
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DOI：
10.1016/j.msea.2012.12.062
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发表时间：
2013-03-10
期刊：
影响因子：
6.4
通讯作者：
Kim, H. K.
中科院分区：
文献类型：
--
作者：
Akbaripanah, F.;Fereshteh-Saniee, F.;Kim, H. K.
通过疲劳寿命和疲劳裂纹扩展速率试验，研究了等通道转角挤压（ECAP）工艺制备的AM60镁合金的疲劳行为。在220 ℃下经过6道次ECAP后，材料的晶粒组织从19.2 μ m细化到2.3 μ m。合金的屈服应力（YS）和极限抗拉强度（UTS）在两道次后达到峰值，但随着道次的增加，晶粒尺寸逐渐变细，随着道次的增加，屈服应力和极限抗拉强度逐渐降低。这是由于织构各向异性引起的软化效应超过了晶粒细化引起的强化效应。织构和塑性诱导裂纹闭合也是影响ECAP镁合金裂纹扩展速率的主要因素。第2道次ECAP后，疲劳寿命也有较大提高。该结果是显著的，因为对于低循环和高循环状态都获得了改善。研究结果表明，AM60镁合金两道次疲劳性能优于多道次疲劳性能。(C)2012爱思唯尔有限公司版权所有。
The fatigue behavior of AM60 magnesium alloy produced by equal channel angular pressing (ECAP) process was investigated by means of fatigue life (S-N) and fatigue crack propagation rate tests. The grain structure of the material was refined from 19.2 mu m to 2.3 mu m after 6 passes of ECAP at 220 degrees C. The yield stress (YS) and ultimate tensile strength (UTS) of the alloy increased to their peak values after two passes but decreased with any further pressing, although the grain size became finer with increasing the number of passes. This is owing to the fact that the softening effect caused by texture anisotropy overwhelmed the strengthening effect due to grain refinement. The texture together with the plasticity-induced crack closure were also the main factors influencing the crack growth rate of the ECAPed Mg alloys. A large enhancement in the fatigue lifetime was also achieved after the 2nd pass of ECAP. This result was remarkable because the improvement was obtained for both the low and high cycle regimes. The present research work has shown that two passed AM60Mg alloy was better than the multi-passed material in view of the fatigue performance. (C) 2012 Elsevier B.V. All rights reserved.