顯微組織和力學(xué)性能
(1. 長(zhǎng)春工業(yè)大學(xué) 化學(xué)與生命科學(xué)學(xué)院，長(zhǎng)春 130012；
2. 中國(guó)科學(xué)院 長(zhǎng)春應(yīng)用化學(xué)研究所 稀土資源利用國(guó)家重點(diǎn)實(shí)驗(yàn)室，長(zhǎng)春 130022；
3. 中國(guó)科學(xué)院 研究生院，北京 100039)
摘 要: 采用高壓壓鑄方法制備了Mg-4Al-0.4Mn-xPr(x = 0, 1, 2, 4, 6, 質(zhì)量分?jǐn)?shù)，%)系列鎂合金，利用X射線衍射儀、場(chǎng)發(fā)射環(huán)境掃描電子顯微鏡、顯微硬度測(cè)試、拉伸和壓縮性能測(cè)試以及斷口分析等手段研究了Pr對(duì)高壓壓鑄Mg-4Al基合金微觀組織和力學(xué)性能的影響。結(jié)果表明：高硬度合金鑄造表面層與表面層中的高Pr含量和細(xì)密的組織有關(guān)；隨著Pr添加量的增加，Al2Pr和Al11Pr3相在晶界附近形成，且其相對(duì)比例隨之變化，同時(shí)合金組織被明顯細(xì)化；添加約4%Pr(質(zhì)量分?jǐn)?shù))的合金具有最佳的力學(xué)性能，良好的力學(xué)性能從室溫一直保持到200 ℃；合金力學(xué)性能的提高主要由于合金致密的鑄造表面層、大量第二相聚集晶界帶來(lái)的晶界強(qiáng)化和細(xì)晶強(qiáng)化以及固溶強(qiáng)化所致。
關(guān)鍵字: 鎂合金；Pr；微觀組織；力學(xué)性能
high-pressure die-cast Mg-4Al-0.4Mn-xPr alloys
（1. School of Chemistry and Life Science, Changchun University of Technology, Changchun 130012, China;
2. State Key Laboratory of Rare Earth Resources Application, Changchun Institute of Applied Chemistry,
Chinese Academy of Sciences, Changchun 130022, China;
3. Graduate School of Chinese Academy of Sciences, Beijing 100049, China）
Abstract: Mg-4Al-0.4Mn-xPr (x=0, 1, 2, 4 and 6, mass fraction, %) magnesium alloys were prepared by high-pressure die-casting technique. The effect of Pr on the microstructures and mechanical properties of die-cast Mg-4Al based alloy were investigated by XRD, FESEM, microhardness test, tensile and compressive properties tests and analysis of fracture surface. The results show that the fine rigid skin region is related to the aggregation of Pr and fine microstructure. Al2Pr and Al11Pr3 phases are mainly concentrated along the grain boundaries, and the relative ratio of the above two phases is in correlation with the Pr content in the alloy. Meanwhile, the grain sizes are greatly reduced with increasing Pr content. The mass fraction of Pr around 4% is considered to be suitable to obtain the optimal mechanical properties those can keep well until 200 ℃. The outstanding mechanical properties are mainly resulted from the rigid casting surface layer, grain boundary strengthening obtained by an amount of precipitates, grain refinement strengthening, as well as solid solution strengthening.
Key words: magnesium alloy; Pr; microstructure; mechanical properties
