摘要
采用金相显微镜、XRD物相分析、透射电镜观察和力学性能测试,研究了真空感应熔炼水冷铜模铸造下Al-8.2Zn-2.05Mg(10Zn-2.5Mg,12Zn-3Mg)-2.2Cu-0.1Mn-0.25Zr合金析出相的强化效应,以及第1种合金在形变热处理工艺下引入的亚晶强化效应。结果表明,3种合金在T6(120℃时效24h)状态下均析出了均匀弥散的强化相η′,此时析出相强化起主导作用。随着Zn、Mg含量的提高,析出强化相的数量逐渐增多,析出相强化效应增大,3种合金的抗拉强度分别为646.2、697.4和732.5MPa,伸长率分别为13.0%、10.6%和7.1%,抗拉强度与其析出相强化效应对应;采用120℃预时效12h+120℃温变形30%+120℃终时效10h的形变热处理工艺可使Al-8.2Zn-2.05Mg-2.2Cu-0.1Mn-0.25Zr合金获得亚晶组织,此时合金为亚晶强化与析出相强化共同作用的强化机制,合金的抗拉强度达到752.3MPa,伸长率为6.7%;亚晶内析出均匀弥散强化相提高合金性能,比单一增加析出相数量效果更好。
Effects of precipitates strengthening on vacuum inductive melting copper mould water-cooled casting alloys, such as Al-8.2Zn-2.05Mg（10Zn-2.5Mg, 12Zn-3Mg）-2.2Cu-0.1Mn-0.25Zr, and subgrains strengthening introduced by thermo-mechanical treatment on the Al-8.2Zn-2.05Mg-2.2Cu-0.1Mn-0.25Zr alloy were investigated by optical microscope （OM）, XRD phase analysis, transmission electron microscope（TEM） and tensile tests. The results show that there exist uniform dispersedly strengthening phase η′ in three kinds of alloys with T6 treatment（ageing 120 ℃ at 24 h）, where precipitation strengthening plays a dominant role. With the increase of Zn、Mg content, the amount of precipitated phases is increased gradually, resulting in simultaneous enhancement of precipitation strengthening effect. The tensile strength of the three alloys reaches 646.2 MPa, 697.4 MPa, 732.5 MPa, respectively, corresponding to its precipitation strengthening effect, and the elongation is 13.0%, 10.6%, 7.1%, respectively. Al-8.2Zn-2.05Mg-2.2Cu-0.1Mn-0.25Zr alloy can obtain subgrains structure by using thermo-mechanical treatment including pre-ageing at 120 ℃ for 12 h ＋30% warm deformation at 120 ℃＋final-ageing at 120 ℃ for 10 h , where the strengthening mechanisms of the alloy is characterized by co-action of subgrains strengthening and precipitation strengthening, and tensile strength and elongation reach up to 752.3 MPa and 6.7%, respectively. Subgrains with uniform dispersedly strengthening phases distributing inside are more favorable to the properties of alloy than increasing number of precipitated phases only.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2012年第11期1062-1066,共5页
Special Casting & Nonferrous Alloys
