Effect of pre-stretching on microstructure of aged 2524 aluminium alloy

预拉伸对时效2524铝合金微观组织的影响(英文)

The effects of pre-stretching following solution treatment on the hardness and microstructures of aged 2524 aluminium alloy at 170 ℃ were studied.Ageing hardness values under different pre-stretching conditions were measured,and the corresponding microstructures were characterized by transmission electron microscopy（TEM）.The results show that compared with unstretched samples,the peak hardness is increased and the time to reach the peak hardness is reduced with the increase of pre-strain;the number density of S（Al2CuMg） phases is increased and the length is shortened in pre-stretched alloy.Additionally,the number density of GPB zones is decreased with the increase of pre-strain in peak-aged samples.When the pre-strain is up to 5%,S phases play the predominant contribution to the peak hardness.Fine and uniformly distributed S phases lead to a higher hardness than GPB zones together with S phases existing in conventionally aged 2524 alloy.

研究了2524铝合金在固溶处理后立即预拉伸对随后在170°C时效的硬度和微观组织的影响。测量了在不同预拉伸条件下的时效硬度,并通过透射电镜观察其微观组织。结果表明:与未拉伸样品相比,随着预拉伸量的增加,预拉伸样品的峰值硬度值逐渐增加,而达到峰值硬度所需的时间也逐渐缩短;预拉伸合金中,S(Al2CuMg)相的数量增多,但其长度缩短;此外,峰值状态GPB区的密度随着应变量的增加而减小。当预拉伸应变达到5%时,S相对峰值状态起主要作用。常规时效的2524合金在峰值时以GPB区和S相为主,在预拉伸样品中更弥散、细小的S相导致硬度值高于常规时效的值。