Shi Xuezhi, Long Yunqian, Zhang Huiqiu, Chen Liqiao, Zhou Yingtang, Yu Xiaoming, Yu Xuan, Cai Lu, Leng Zhe
Innovation and Application Institute, Zhejiang Ocean University, Zhoushan 316022, China.
Materials (Basel). 2019 Feb 6;12(3):498. doi: 10.3390/ma12030498.
In this work, the role of long period stacking ordered (LPSO) phase in the crack propagation behavior of an as-cast MgY₃Zn alloy was investigated by dynamic four-point bent tests. The as-cast MgY₃Zn alloy is mainly composed of Mg matrix, 18R LPSO phase located at the grain boundaries and 14H LPSO phase located within the Mg matrix. The alloy exhibits excellent dynamic mechanical properties; the yield stress, maximum stress and strain to failure are 190.51 ± 3.52 MPa, 378.32 ± 4.26 MPa and 0.168 ± 0.006, respectively, at the strain rate of ~3000 s. The LPSO phase effectively hinders dynamic crack propagation in four typical ways, including crack tip blunting, crack opening inhibition, crack deflection and crack bridging, which are beneficial to the mechanical properties of the alloy under dynamic loadings.
在本研究中，通过动态四点弯曲试验研究了长周期堆垛有序（LPSO）相在铸态MgY₃Zn合金裂纹扩展行为中的作用。铸态MgY₃Zn合金主要由Mg基体、位于晶界处的18R LPSO相和位于Mg基体内的14H LPSO相组成。该合金表现出优异的动态力学性能；在应变率约为3000 s⁻¹时，屈服应力、最大应力和断裂应变分别为190.51±3.52 MPa、378.32±4.26 MPa和0.168±0.006。LPSO相通过裂纹尖端钝化、裂纹张开抑制、裂纹偏转和裂纹桥接这四种典型方式有效阻碍动态裂纹扩展，这有利于合金在动态载荷下的力学性能。
