摘要
A ZM51 magnesium alloy joint with high intensity and thermal conductivity was fabricated using friction stir welding(FSW)followed by aging heat treatment(AG).During the FSW process,β_(1)'andβ_(2)'phases formed in the heat-affected zone(HAZ),yet new phases were absent in both the stirring zone(SZ)and thermal mechanical affected zone(TMAZ).After AG,numerousβ_(1)'andβ_(2)'phases emerged in the SZ and the TMAZ of the joint,while only theβ_(2)'phase precipitated in the HAZ.Due to precipitation strengthening,the average microhardness,yield strength and ultimate tensile strength of the joint reached up to 98%,94%and 88%those of the base metal(BM),respectively.Notably,basal slip{0001}<1120>,and twinning at 60°/<1010>and 86°/<1120>were more prevalent in TMAZ,contributing to the joint’s fracture.Furthermore,the precipitation ofβ_(1)'andβ_(2)'phases enhanced the joint’s thermal conductivity,averaging 121.7 W/(m·K),being 112%that of BM.
采用搅拌摩擦焊接(FSW)和时效热处理(AG)制备了具有高强度、高热导率的ZM51镁合金接头。在FSW过程中,热影响区(HAZ)生成了β_(1)'相和β_(2)'相,而搅拌区(SZ)和热机械影响区(TMAZ)无新相生成。AG后,大量β_(1)'相和β_(2)'相在SZ和TMAZ中析出,而HAZ中仅有β_(2)'相析出。由于析出强化作用,接头的平均显微硬度、屈服强度和极限抗拉强度分别达到母材(BM)的98%、94%和88%。值得注意的是,TMAZ更容易发生{0001}<1120>基面滑移和60°/<1010>及86°/<1120>孪生,导致接头断裂于TMAZ。此外,β_(1)'相和β_(2)'相的析出提升了接头的热导率,平均热导率为121.7 W/(m·K),达到BM的112%。
基金
supported by the Key Research and Development Program of Shaanxi Province,China(No.2017ZDXM-GY-037)
the National Natural Science Fund for Excellent Young Scholars,China(No.52222410)
the National Natural Science Foundation of China(Key Program)(No.52034005)
the National Natural Science Foundation of China(No.52227807)
the National Key Research and Development Program of China(No.2021YFB3700902)
the Shaanxi Province Qinchuangyuan“Scientist+Engineer”Team Program,China(No.2022KXJ-072).
