(1. 西安理工大學 材料科學與工程學院，西安 710048；
2. 廣東省科學院 新材料研究所 廣東省金屬強韌化技術(shù)與應(yīng)用重點實驗室，粵港輕合金先進制造技術(shù)聯(lián)合研發(fā)中心，廣州 510650)
摘 要: Mg-8Gd-4Y-1Zn-0.5Al(質(zhì)量分數(shù)，%)合金鑄態(tài)試樣經(jīng)均勻化和熱擠壓后獲得擠壓板材，分別對均勻化板材和擠壓板材進行室溫軋制和時效處理；采用OM、SEM、TEM和EBSD分析其微觀組織結(jié)構(gòu)，同時測試其硬度和拉伸力學性能，旨在研究上述合金在不同加工工藝下的組織與力學性能演變。結(jié)果表明：經(jīng)室溫軋制的均勻化板材組織由等軸晶轉(zhuǎn)變?yōu)榘橛袑\晶的變形晶粒，再結(jié)晶處理后轉(zhuǎn)變?yōu)殪o態(tài)再結(jié)晶晶粒；18R-LPSO結(jié)構(gòu)發(fā)生收縮、聚集。峰時效處理后，部分晶粒內(nèi)部析出大量層錯和β′相，規(guī)定塑性延伸強度(Rp0.2)與抗拉強度較時效前分別提高24%和23%；室溫軋制后，擠壓板材的再結(jié)晶晶粒尺寸稍微增大，18R-LPSO結(jié)構(gòu)出現(xiàn)不規(guī)則的彎曲與分層現(xiàn)象；時效后，板材的規(guī)定塑性延伸強度、抗拉強度和伸長率分別達到383 MPa、420 MPa和5.5%。
關(guān)鍵字: 稀土鎂合金；長周期堆垛有序(LPSO)結(jié)構(gòu)；軋制；微觀組織；力學性能
（1. School of Materials Science and Engineering, Xi’an University of Technology, Xi’an 710048, China;
2. Guangdong-Hong Kong Joint Research and Development Center on Advanced Manufacturing Technology for Light Alloys, Guangdong Provincial Key Laboratory of Metal Toughening Technology and Application, Institute of New Materials, Guangdong Academy of Sciences, Guangzhou 510650, China）
Abstract:The as-cast samples of Mg-8Gd-4Y-1Zn-0.5Al (mass fraction, %) alloy were homogenized and hot-extruded to obtain extruded sheets. And then, the homogenized and extruded sheets were rolled at room temperature and aged, respectively. The microstructures and phase compositions of the samples were analyzed by OM, SEM, TEM and EBSD. Meanwhile, the hardness and tensile mechanical properties of the samples were tested. The aim is to study the evolution on the microstructure and mechanical properties of the alloy under different processing technologies. After rolling at room temperature, the structure transforms from equiaxed crystals into deformed grains accompanied by twins, and then transforms into static recrystallized grains after the recrystallization treatment. Meanwhile the 18R-LPSO structure shrinks and aggregates. After peak aging treatment, a large number of stacking faults and β′ phases precipitate in some grains. The yield strength (YS) and tensile strength (UTS) of the sheet are enhanced by 24% and 23% compared with those before aging, respectively. After rolling at room temperature, the recrystallized grain size of extruded sheet increases slightly, and 18R-LPSO structure appears irregular bending and delamination. After aging, the YS, UTS and Elongation (EL) of the sheet reach 383 MPa, 420 MPa and 5.5%, respectively.
Key words: Mg-rare earth alloy; long-period stacking ordered (LPSO); rolling; microstructure; mechanical property
