摘要
利用Gd(0.00%,0.25%,0.50%,0.75%,1.00%,质量分数,下同)元素和凝固压力(3 GPa)调控Mg-5Al合金凝固组织结构,对合金样品进行压缩测试,并研究组织结构与室温压缩性能相关性。结果表明:常压石墨型铸造下,仅Mg-5Al-0.75Gd合金获得了晶界无共晶相生成、粒状Al2Gd相弥散分布在基体上、晶粒平均尺寸约为85μm的固溶体组织,其抗压强度和最大压缩应变分别为379 MPa和33.46%,高于存在晶间第二相的合金。3 GPa高压下,Gd含量≤0.25%合金的凝固组织为单一固溶体,Gd含量≥0.50%合金的晶界(枝晶间)有共晶Al_(2)Gd相生成。固溶体Mg-5Al-0.25Gd合金的平均晶粒尺寸是74μm,抗压强度是402 MPa,最大压缩应变是33.61%。Mg-5Al-0.75Gd合金的平均晶粒尺寸是38μm,抗压强度和最大压缩应变分别是341 MPa和25.12%,其性能低于Mg-5Al-0.25Gd合金。可见,晶间Al,Gd元素的存在形式是影响铸造Mg-Al合金力学性能的重要因素。
The solidification microstructure of the Mg-5Al alloy is controlled by the Gd content(0.00%,0.25%,0.50%,0.75%,1.00%,mass fraction,the same below)and high pressure(3 GPa),and the correlation between microstructure and compressive properties at room temperature was studied.The results show that the microstructure is single solid solution only when the the content of Gd is 0.75%,for the Mg-5Al-xGd alloys solidified under atmospheric pressure graphit mold casting.In the Mg-5Al-0.75Gd alloy,no eutectic phase form at the grain boundaries,granular Al_(2)Gd phase is dispersed on the matrix,and the average grain size is about 85μm.Moreover,the compressive strength and the maximum compressive strain of the Mg-5Al-0.75Gd alloy solidified under atmospheric pressure are 379 MPa and 33.46%respectively,which are higher than those of alloys with intergranular second phase.For the Mg-5Al-xGd alloys solidified under 3 GPa pressure,the microstructure is single solid solution when the Gd content is≤0.25%,and there are eutectic phase Al2Gd at the grain boundaries(among dendrites)when the Gd content is≥0.50%.In addition,the grain sizes of the Mg-5Al-0.25Gd and Mg-5Al-0.75 Gd alloys solidified under 3 GPa pressure are 74μm and 38μm respectively.However,the compressive strength and the maximum compressive strain of the Mg-5Al-0.25Gd alloy are 402 MPa and 33.61% respectively,which are superior than that of the Mg-5Al-0.75Gd alloy with the compressive strength of 341 MPa and the maximum compressive strain of 25.12%.Therefore,the existence form of Al and Gd at grain boundaries is an important factor affecting the mechanical properties of the Mg-5Al-xGd alloys.
作者
张苑琳
阔洋
杨雨森
房大然
代鹏林
靳康帅
林小娉
ZHANG Yuanlin;KUO Yang;YANG Yusen;FANG Daran;DAI Penglin;JIN Kangshuai;LIN Xiaoping(School of Resources and Materials,Northeastern University at Qinhuangdao,Qinhuangdao 066004,Hebei,China;School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China)
出处
《材料工程》
EI
CAS
CSCD
北大核心
2023年第1期95-103,共9页
Journal of Materials Engineering
基金
国家自然科学基金面上项目(51675092)
河北省自然科学基金面上项目(E2021501019,E2022501001)。
