(1. 華北理工大學(xué) 冶金與能源學(xué)院 軍用關(guān)鍵材料國(guó)防特色學(xué)科，唐山 063210；
2. 現(xiàn)代冶金技術(shù)教育部重點(diǎn)實(shí)驗(yàn)室，唐山 063210)
摘 要: 通過大擠壓比熱擠壓工藝制備出含有長(zhǎng)周期堆垛有序(LPSO)相的高強(qiáng)塑性Mg-8.34Gd-2.32Y-1.04Zn-0.07Zr合金。通過金相顯微鏡、EBSD、TEM等顯微檢測(cè)方法及數(shù)學(xué)模型研究了合金顯微組織與力學(xué)性能之間的關(guān)系。結(jié)果表明，合金經(jīng)熱擠壓后形成了雙峰結(jié)構(gòu)，在時(shí)效處理后同時(shí)存在14H-LPSO相和β′析出相。合金獲得了較好的力學(xué)性能，抗拉強(qiáng)度、屈服強(qiáng)度和伸長(zhǎng)率分別達(dá)到463.1 MPa，392.6 MPa和13.3%。合金屈服強(qiáng)度以細(xì)晶強(qiáng)化、析出強(qiáng)化和固溶強(qiáng)化的貢獻(xiàn)為主。高占比的細(xì)小再結(jié)晶晶粒、弱織構(gòu)以及LPSO相的存在對(duì)合金塑性的提升有重要作用。
關(guān)鍵字: 大擠壓比；Mg-Gd-Y-Zn-Zr合金；雙峰結(jié)構(gòu)；LPSO相；強(qiáng)韌化機(jī)理
（1. Discipline of Key Materials for Defense Industry, College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, China;
2. Key Laboratory of Modern Metallurgy, Ministry of Education, Tangshan 063210, China）
Abstract:The Mg-8.34Gd-2.32Y-1.04Zn-0.07Zr alloy containing long-period stacking order (LPSO) phase with good combined strength and ductility was prepared by large-strain hot extrusion. By the analysis via optical microscopy, EBSD, TEM and mathematical models, the relationship between microstructure and mechanical properties of the alloy was studied. The results show that a bimodal structure forms after hot extrusion. After an artificial ageing treatment, the 14-H LPSO phase and β′ phase are both observed. The alloy exhibits good mechanical properties. The tensile strength, yield strength and elongation are 463.1 MPa, 392.6 MPa and 13.3%, respectively. Grain boundary strengthening, precipitation strengthening and solid solution strengthening provide the most significant contribution to the yield strength of the alloy. The high ratio of fine recrystallized grains, the weak texture as well as the presence of LPSO phase play important roles in the enhancement of ductility of the alloy.
Key words: large-strain; Mg-Gd-Y-Zn-Zr alloy; bimodal structure; LPSO phase; strengthening-toughening mechanism
