纤维状γ-Mg_(17)Al_(12)共晶相的制备及其对镁合金力学性能的影响  

Preparation and Its Effect of Fibrous γ-Mg_(17)Al_(12) Eutectic Phase on Mechanical Properties of Mg Alloy

作　　者：徐畅 张祝群 代鹏林 阔洋 林小娉 XU Chang;ZHANG Zhu-qun;DAI Peng-lin;KUO Yang;LIN Xiao-ping(School of Materials Science and Engineering,Northeastern University,Shenyang 110819,Liaoning,China;School of Resources and Materials,Northeastern University at Qinhuangdao,Qinhuangdao 066004,Hebei,China)

机构地区：[1]东北大学材料科学与工程学院,辽宁沈阳110819 [2]东北大学秦皇岛分校资源与材料学院,河北秦皇岛066004

出　　处：《铸造》2021年第8期915-920,共6页Foundry

基　　金：国家自然科学基金(51675092、51775099);河北省自然科学基金面上项目(E2018501033、E2018501032)。

摘　　要：利用CS-1V型六面顶液压机在4 GPa高压下对Mg-Al二元合金进行凝固,使用SEM、XRD等分析手段研究了高压下共晶γ-Mg_(17)Al_(12)与α-Mg相界面、形貌、数量以及试验合金力学性能提升机制。结果表明,4 GPa高压下,Mg-Al二元合金α-Mg枝晶间初始发生共晶转变的原始合金Al量由石墨型(5℃水冷,常压)的7%提高到15%,共晶相γ-Mg_(17)Al_(12)形貌由常压下棒间距为1500 nm的棒状共晶转变为高压下层片间距仅有50 nm的纤维状,经计算高压下γ-Mg_(17)Al_(12)相/α-Mg间面点阵错配度为5.5%。高压下纤维状共晶γ-Mg_(17)Al_(12)相所产生的第二相强化与α-Mg枝晶组织细晶所产生的细晶强化、Al溶质在α-Mg基体中固溶量增大所产生的固溶强化等综合强化效应使高压凝固Mg-15Al和Mg-20Al合金具有高硬度(>HV100)、高强度(>500 MPa),同时还维持一定的塑性(>20.0%)。CS-1 V hexahedron hydraulic press was used to solidify Mg-Al binary alloy under 4 GPa high pressure, and SEM and XRD were used to investigate the morphology, quantity, boundary surface between eutectic γ-Mg_(17)Al_(12) and α-Mg phase, and the mechanism of the mechanical properties improvement under high pressure. The results show that, under 4 GPa high pressure, the amount of Al needed for the eutectic transformation to form γ-Mg_(17)Al_(12) phase in the base alloy between α-Mg dendrites of Mg-Al binary alloy is increased from 7%(graphite mold, water cooling at 5 ℃, normal pressure) to 12%;meanwhile, the morphology of the γ-Mg_(17)Al_(12) phase changes from rod shape with rod spacing of 1500nm under normal pressure to fiber shape with sheet spacing of 50 nm under high pressure. The lattice mismatch between fibrous γ-Mg_(17)Al_(12) phase and α-Mg is calculated to be 5.5%. Under high pressure, the comprehensive strengthening effects of the second phase strengthening, grain refinement strengthening and solid solution strengthening produced by the fibrous eutectic phase make the high-pressure solidified Mg-15 Al and Mg-20 Al alloys have high hardness(>HV100) and high strength(>500 MPa), and still maintain a certain degree of plasticity(>20.0%).

关 键 词：MG-AL合金 高压凝固 共晶相 高强度 

分 类 号：TG113.25[金属学及工艺—物理冶金]