摘要
对热挤压、时效处理(T5态)及固溶+时效处理(T6态)Mg-7%Zn-0.6%Zr-0.5%Y合金(质量分数)分别进行了低周疲劳实验,探讨了热处理对合金低周疲劳变形行为的影响.结果表明:时效处理和固溶+时效处理可提高热挤压Mg-7%Zn-0.6%Zr-0.5%Y合金的循环变形抗力;时效处理降低了合金的疲劳寿命,固溶+时效处理可以提高合金在较高外加总应变幅下的疲劳寿命,但降低合金在较低外加总应变幅下的低周疲劳寿命;不同状态合金的弹性应变幅和塑性应变幅与载荷反向周次的关系可分别用Basquin和Coffin-Manson公式来描述;时效及固溶+时效处理过程中形成的长周期堆垛有序结构(LPSO相)是合金的循环变形抗力大幅提高的主要原因,而疲劳变形过程中形成的孪晶可能是时效态合金疲劳寿命降低的原因.
The low-cycle fatigue tests have been conducted for the Mg-7%Zn-0.6%Zr-0.5%Y alloys（mass fraction） subjected to extrusion, aging（T5） and solution plus aging（T6） treatment, respectively. The influence of heat treatment on the fatigue deformation behavior of the alloy has also been systematically investigated. The results show that T5 and T6 treatment can improve the cyclic deformation resistance of Mg-7%Zn-0.6%Zr-0.5%Y alloys. T5 treatment can reduce the fatigue life of the alloy. However, T6 treatment can improve the fatigue life at high total strain amplitudes, and reduce the fatigue life at low total strain amplitudes. The relationship between elastic strain amplitude, plastic strain amplitude and reversals to failure of the alloys can be described by Basquin and Coffin-Manson equations, respectively. For the alloys subjected to both T5 and T6 treatments, the increase in the cyclic deformation resistance is mainly due to the formation of long period stacking ordered（LPSO） phase. The twins formed during the fatigue deformation may be responsible for the decrease in the fatigue life of the alloy subjected to T5 treatment.
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2014年第6期700-706,共7页
Acta Metallurgica Sinica
关键词
镁合金
低周疲劳
循环变形
热处理
magnesium alloy
low-cycle fatigue
cyclic deformation
heat treatment
