材料期刊网

通过对挤压变形Mg--x%Al--3%Ni(x=4, 5, 6, 7, 质量分数)合金进行总应变控制模式的室温疲劳实验, 研究了不同Al含量的挤压变形Mg--x%Al--3%Ni合金的循环应力响应、疲劳寿命和循环应力--应变行为. 结果表明: 不同Al含量的挤压变形Mg--x%Al--3%Ni合金均表现为循环应变硬化; 挤压变形Mg--x%Al--3%Ni合金的应变疲劳寿命与塑性应变幅、弹性应变幅间的关系分别服从Coffin--Manson和Basquin关系式.

Due to the low density, high specific strength and stiffness, magnesium alloys are being considered for automotive and aerospace applications. The structural applications of magnesium components need a decent low--cycle fatigue performance, because cyclic loading is often encountered. In order to identify the low--cycle fatigue behavior of the newly developed Mg--x%Al--3%Ni(x=4, 5, 6, 7, mass fraction) extruded magnesium alloys with different contents of Al, the total strain--controlled low--cycle fatigue tests were performed at room temperature. The cyclic stress response, strain fatigue life and cyclic stress--strain behaviors were investigated for the hot--extruded Mg--x%Al--3%Ni alloys. The results of the low--cyclic fatigue tests show that the hot--extruded Mg--x%Al--3%Ni alloys exhibit the cyclic strain hardening during fatigue deformation. The dependences of the strain fatigue life on plastic strain amplitude and elastic strain amplitude can be described by the Coffin--Manson and Basquin equations, respectively. In the hot extruded Mg--x%Al--3%Ni alloys with different contents of Al, the extruded Mg--5%Al--3%Ni alloy gives the longest fatigue life and the highest fatigue resistance. In addition, a linear relation between the cyclic stress amplitude and cyclic strain amplitude can be noted for the hot--extruded Mg--x%Al--3%Ni alloys.