Al-Cu-Mg-Ag轮毂锻件的热稳定性

Thermal stability of Al-Cu-Mg-Ag hub forgings

以峰时效态的Al-Cu-Mg-Ag轮毂锻件为研究对象,研究锻件不同热暴露温度和热暴露时间的室温拉伸性能和高温拉伸性能,并对锻件在不同温度下的热稳定性进行对比和分析,结果表明:Al-Cu-Mg-Ag锻件具有良好的热稳定性,在150℃暴露1~100 h后,室温拉伸性能和高温拉伸性能无显著变化;在150~200℃短时间热暴露1 h不会降低综合性能,但随着热暴露温度的升高和热暴露时间的延长,Al-Cu-Mg-Ag锻件强度产生不同程度的下降;在200℃和250℃暴露100 h后,室温屈服强度分别剩余61.1%和37.2%,室温抗拉强度分别剩余77.8%和60.8%,高温屈服强度分别剩余61.6%和42.8%,高温抗拉强度分别剩余67.5%和47.6%;Al-Cu-Mg-Ag锻件的主要析出相为Ω相和θ′相,在Kt=1和R=0.1的实验条件下,200℃/10 h热暴露后的室温疲劳极限为278 MPa,相比热暴露前的疲劳极限311 MPa降低了10.6%。

The room temperature tensile properties and elevated temperature tensile properties of peak aged Al-Cu-Mg-Ag hub forgings after different heat exposure temperatures and heat exposure time were tested,and the thermal stabilities of the forgings at different temperatures were compared and analyzed.The results show that Al-Cu-Mg-Ag forgings exhibit good thermal stability.After exposure at 150℃for 1 to 100 h,there were no significant changes in room temperature tensile properties and elevated temperature tensile properties.Short time heat exposure at 150-200℃for 1 h does not reduce the overall performance,but the strength of Al-Cu-Mg-Ag forgings decreases with the increase of heat exposure temperature and the extension of heat exposure time.After 100 h of exposure at 200℃and 250℃,the room temperature yield strength remains 61.1%and 37.2%,and the room temperature tensile strength remains 77.8%and 60.8%,the elevated temperature yield strength remains 61.6%and 42.8%,and the elevated temperature tensile strength remains 67.5%and 47.6%,respectively.The main precipitates of Al-Cu-Mg-Ag forgings areΩphase andθ′phase.Under the experimental conditions of Kt=1 and R=0.1,the room temperature fatigue limit after 200℃/10 h heat exposure is 278 MPa,which is 10.6%lower than the fatigue limit of 311 MPa before heat exposure.