【摘要】：通過在Mg-6Zn合金中添加0.4%Zr和2%Sm(質(zhì)量分?jǐn)?shù))制備出一種新型Mg-6Zn-2Sm-0.4Zr合金;利用光學(xué)顯微鏡(OM)、掃描電鏡(SEM)及能譜儀(EDS)、X射線衍射儀(XRD)、顯微硬度及力學(xué)性能測試研究鑄造Mg-6Zn-2Sm-0.4Zr合金在鑄態(tài)、固溶、時效處理下的顯微組織和力學(xué)性能的變化。結(jié)果表明:合金鑄態(tài)組織主要由基體α-Mg、晶界處呈連續(xù)或半連續(xù)分布的(α-Mg+Mg_2Zn_3+Mg_(41)Sm_5)共晶和晶內(nèi)孤立的點狀相組成。合金在440和450℃固溶12~36 h時間范圍內(nèi),隨著時間和溫度的增加,固溶效果逐漸增強(qiáng)。當(dāng)在450℃固溶28 h時獲得了較好的顯微組織,抗拉強(qiáng)度為230 MPa,伸長率為9.58%。隨后經(jīng)200℃時效6~48 h后,合金的力學(xué)性能明顯提高,時效強(qiáng)化效應(yīng)隨時間的延長呈先增加后減小的趨勢,其中時效12 h時同時出現(xiàn)了抗拉強(qiáng)度和伸長率的峰值258 MPa和14.43%,比鑄態(tài)的分別提高44 MPa和90.80%。
[Abstract]:A new type of Mg-6Zn-2Sm-0.4Zr alloy was prepared by adding 0.4%Zr and 2%Sm (mass fraction) to Mg-6Zn alloy. The microhardness and mechanical properties of cast Mg-6Zn-2Sm-0.4Zr alloy were studied by (OM), scanning electron microscopy (SEM) and energy dispersive (EDS), X-ray diffractometer (XRD),). Changes of microstructure and mechanical properties under aging treatment. The results show that the as-cast microstructure of the alloy is mainly composed of (偽-Mg, _ (41) Sm_5) eutectic with a continuous or semi-continuous distribution at the grain boundary of the matrix and an isolated dot phase within the crystal. In the time range of 440 鈩，

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