Effect of cooling rate on the microstructure evolution and mechanical properties of homogenized Mg–Gd–Y–Zn–Zr alloy
Effect of cooling rate on the microstructure evolution and mechanical properties of homogenized Mg–Gd–Y–Zn–Zr alloy
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DOI：
10.1016/j.msea.2012.08.112
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发表时间：
2013
期刊：
影响因子：
6.4
通讯作者：
Chao Xu;M. Zheng;K. Wu;E. Wang;G. Fan;S. W. Xu;S. Kamado;X. D. Liu;G. Wang;X. Lv
中科院分区：
文献类型：
--
作者：
Chao Xu;M. Zheng;K. Wu;E. Wang;G. Fan;S. W. Xu;S. Kamado;X. D. Liu;G. Wang;X. Lv
采用温水淬火和炉内冷却两种冷却方式对Mg-8.2Gd-3.8Y-1.0Zn-0.4Zr（wt%）合金进行均匀化处理。研究了均匀化处理后合金的组织演变和力学性能。淬火态试样由α-Mg基体、分布于晶界的Mg 5 RE相和18 R LPSO相以及少量随机分布的富RE颗粒组成。在炉内冷却过程中，由于溶质原子向α-Mg基体中的扩散，Mg 5 RE和18 R LPSO相分别转变为块状14 H LPSO相和片状14 H LPSO相。此外，片状14 H LPSO相生长并贯穿整个晶粒。淬火态试样的抗拉屈服强度为130 MPa，极限抗拉强度为206 MPa，断裂伸长率为5.5%，而炉冷态试样的抗拉屈服强度较高，但由于晶粒粗大和形成块状的14 H LPSO相，其极限抗拉强度和塑性较低。
Different cooling processes, such as quenching in warm water and cooling in furnace, were introduced to homogenize Mg–8.2Gd–3.8Y–1.0Zn–0.4Zr (wt%) alloy. Microstructure evolution and mechanical properties of the homogenized alloy were investigated. The as-quenched sample was comprised of α-Mg matrix, Mg5RE phase and 18R LPSO phase distributed at the grain boundaries and a few of RE-rich particles distributed randomly. During the process of cooling in furnace, Mg5RE and 18R LPSO phases were transformed into block-shaped 14H LPSO phase and lamellar-shaped 14H LPSO phase, respectively, due to the diffusion of solute atoms into the α-Mg matrix. Furthermore, the lamellar-shaped 14H LPSO phase grew and ran through the whole grains. The as-quenched sample exhibits tensile yield strength of 130MPa, ultimate tensile strength of 206MPa and elongation to failure of 5.5%, while the sample cooled in the furnace exhibits higher tensile yield strength but lower ultimate tensile strength and ductility due to the coarse grains and formation of block-shaped 14H LPSO phase.