Lian-Xi Chen, Ying-Yin Sheng, Xiao-Jian Wang*, Xue-Yang Zhao, Hui Liu, Wei Li*, Effect of the microstructure and distribution of the second phase on the stress corrosion cracking of biomedical Mg-Zn-Zr-xSr alloys. Materials, 2018, 11(4).
发布日期: 2018-06-14 发布者: 郑洋 阅读: 23

The stress corrosion cracking (SCC) properties of the bi-directional forged (BDF) Mg-4Zn-0.6Zr-xSr (ZK40-xSr, x = 0, 0.4, 0.8, 1.2, 1.6 wt %) alloys were studied by the slow strain rate tensile (SSRT) testing in modified simulated body fluid (m-SBF). The average grain size of the BDF alloys were approximately two orders of magnitude smaller than those of the as-cast alloys. However, grain refinement increased the hydrogen embrittlement effect, leading to a higher SCC susceptibility in the BDF ZK40-0/0.4Sr alloys. Apart from the grain refinements effectthe forging process also changed the distribution of secondphase from the net-like shape along the grain boundary to a uniformly isolated island shape in the BDF alloysThe SCC susceptibility of the BDF ZK40-1.2/1.6Sr alloys were lower than those of the as-cast alloysThe change of distribution of the second phase suppressed the adverse effect of Sr on the SCC susceptibility in high Sr-containing magnesium alloysThe results indicated the stress corrosion behavior of magnesium alloys was related to the average grain size of matrix and the distribution and shape of the second phase.