Sun Youhong, Ma Shaoming, Wang Huiyuan, Chen Lei, Gao Ke, Ma Yinlong, Liu Baochang
School of Construction Engineering, Jilin University, Changchun 130026, China.
Key Laboratory of Drilling and Exploitation Technology in Complex Conditions, Ministry of Land and Resources, No. 938 Ximinzhu Street, Changchun 130026, China.
Materials (Basel). 2016 Mar 4;9(3):157. doi: 10.3390/ma9030157.
This research was carried out to investigate the influence of Sr-Sb on the microstructures and mechanical properties of Al-18 wt % Mg₂Si-4.5Cu alloys. After the addition of 0.2 wt % Sr-Sb, the morphologies of primary Mg₂Si transformed from equiaxed dendrite to cube in as-cast alloys and the average size of primary Mg₂Si decreased from ~50 to ~20 μm. The shape of eutectic Mg₂Si changed from Chinese script to short rod. After extrusion and T6 heat treatment, the ultimate tensile strength of modified alloy at room temperature (RT) and 100 °C increased respectively from 229 to 288 MPa, and from 231 to 272 MPa. The elongation-to-failure only slightly improved from 2.9% to 3.8% and from 3.3% to 3.7% at RT and 100 °C, respectively. The tensile fracture surface revealed a transition from brittle fracture to ductile fracture after modifying by 0.2 wt % Sr-Sb.
本研究旨在探究Sr-Sb对Al-18 wt% Mg₂Si-4.5Cu合金微观结构和力学性能的影响。添加0.2 wt% Sr-Sb后，铸态合金中初生Mg₂Si的形态从等轴枝晶转变为立方状，且初生Mg₂Si的平均尺寸从约50μm减小至约20μm。共晶Mg₂Si的形状从汉字状变为短棒状。挤压和T6热处理后，变质合金在室温（RT）和100°C下的抗拉强度分别从229 MPa提高到288 MPa，以及从231 MPa提高到272 MPa。室温下和100°C时的断裂伸长率仅分别从2.9%略微提高到3.8%，以及从3.3%略微提高到3.7%。拉伸断口表明，经0.2 wt% Sr-Sb变质处理后，断裂模式从脆性断裂转变为韧性断裂。
