摘要
采用光学显微镜对Mg-xGd-2Y-0.5Zr(x=9,11,13,15 mass%)合金铸态、固溶时效态以及拉伸断口附近纵切面组织进行观察分析,并用扫描电镜和电子拉伸试验机分别对合金断口形貌和不同温度下的力学性能进行测试和分析。研究结果表明:铸态Mg-xGd-2Y-0.5Zr合金经525℃固溶6 h和225℃时效10 h后粗大的枝晶消失,晶界清晰可见;当Gd的添加为13 mass%时,合金的晶粒最细小,组织分布最均匀,Mg-13Gd-2Y-0.5Zr合金具有优异的室温和高温力学性能,其在室温和高温下的抗拉强度达到最大值。当Gd的含量一定时,合金的抗拉强度随拉伸温度的升高先升高后降低,在250℃时达到最大值;Mg-13Gd-2Y-0.5Zr合金断裂形式为脆性断裂,并以沿晶断裂为主。
Microstructure of as cast,solid solution and aged Mg-xGd-2Y-0.5Zr（ x = 9,11,13,15 mass%） alloy and longitudinal section near tensile fracture surface were observed and analyzed by optical microscope. The fracture morphology and mechanical properties of the alloy at different temperatures were measured and analyzed by SEM and tensile test machine,respectively. The results show that after solid solution at 525 ℃ for 6 h and aging at 225 ℃ for 10 h,the bulk dendrites of the as-cast Mg-13Gd-2Y-0.5Zr alloy disappear,and the grain boundaries are clearly visible. When the content of Gd is 13 mass%,the grain of the alloy is finer and the microstructure distribution is homogeneous; Mg-13Gd-2Y-0.5Zr alloy has excellent mechanical properties at room temperature and high temperature,and the tensile strength of the alloy reaches maximum value at room temperature and high temperature. When the content of Gd is constant,the tensile strength of the alloy increases first and then decreases with the increasing of tensile temperature,and reaches the maximum at 250℃. The fracture mechanism of the Mg-13Gd-2Y-0.5Zralloy is brittle fracture,and intergranular fracture is dominant.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2017年第11期21-27,共7页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(51571084
51171059)
河南省重点科技攻关计划资助项目(152102210072)
