Li元素對(duì)熱軋及退火態(tài)AZ31鎂合金板材的組織及力學(xué)性能的影響

Li元素對(duì)熱軋及退火態(tài)AZ31鎂合金板材的組織及力學(xué)性能的影響Effect of Li addition on microstructure and mechanical properties of rolled and annealed AZ31 alloy

通過OM、SEM、拉伸實(shí)驗(yàn)研究添加不同含量的Li元素對(duì)軋制及退火態(tài)AZ31鎂合金組織和力學(xué)性能的影響。結(jié)果表明：添加Li元素的合金板材在熱軋后均有大量孿晶出現(xiàn)。經(jīng)過不同溫度退火處理后，合金板材的力學(xué)性能得到不同程度的改善。LAZ131(Mg-1Li-3Al-1Zn)合金在經(jīng)過150 ℃退火30 min，其沿TD方向拉伸時(shí)力學(xué)性能最佳，抗拉強(qiáng)度、屈服強(qiáng)度、伸長(zhǎng)率分別為335 MPa、261 MPa、14.6%。而LAZ131合金在經(jīng)過300 ℃退火30 min后的力學(xué)性能各向異性最小，且合金的組織為均勻細(xì)小的等軸晶，總的力學(xué)性能較好，抗拉強(qiáng)度、屈服強(qiáng)度及伸長(zhǎng)率分別為259 MPa、174 MPa、23.1%。這是由于Li元素的添加對(duì)基面織構(gòu)的改善以及在300 ℃退火時(shí)的再結(jié)晶所導(dǎo)致。

The microstructure and mechanical properties of rolled and annealed AZ31 alloy with different Li addition were studied by optical microscopy, SEM, and tensile test. The results show that with the increase of lithium additions, the microstructures of rolled alloy with lithium addition exhibit much twins. After annealed at 150 ℃ for 30 min, the LAZ131(Mg-1Li-3Al-1Zn) sheet exhibit higher tensile strength of 335 MPa along TD, with lower elongation of 14.6%. After annealing at 300 ℃ for 30 min, the lower anisotropy and optimal comprehensive mechanical property are achieved in LAZ131(Mg-1Li-3Al-1Zn), with ultimate tensile strength of 259 MPa, yield strength of 174 MPa and elongation of 23.1%. This is attributed to the modification of basal texture due to Li addition and recrystallization when annealing at 300 ℃.

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