摘要
对低压铸造A356.2铝合金轮毂不同形式轮辐取样,进行了微观组织和力学性能测试,并对二次枝晶臂间距、断口形貌及微区成分等进行了分析,研究了轮辐性能的影响因素和断裂机制。结果表明,不同类型轮辐强度整体水平较高而塑性不足,其中屈服强度主要受基体相状态决定因此变化不大;伸长率受铸件内部缺陷控制变化相对较大;抗拉强度变化趋势与伸长率相关。拉伸断口的表面分布着杂质和孔洞等缺陷,经能谱测试,断口表面存在由浇注过程带入的渣滓、氧化膜而引入的C和O元素,Fe元素也在轮辐上相对聚集。断口表面观察到准解理平面及韧窝形貌,说明断裂方式是韧脆混合型断裂,裂纹主要沿枝晶胞之间的共晶区域进行扩展。
The factors affecting the performance and fracture mechanism of low-pressure casting A356.2 aluminum alloy wheel spokes were investigated by analysis of secondary dendrite arm spacing, fracture surface and micro-area composition based on testing mechanical properties and observing microstructure of the samples from different shape aluminum alloy wheel spokes. The results show that different type pokes exhibit high strength and low plasticity, in which the yield strength shows relatively steady because it is mainly controlled by the matrix phase state, and the elongation controlled by the internal defects of castings indicates evident change, and the tensile strength exhibits the same trend as the elongation. The impurities and holes are distributed in the tensile fracture surface, and by spectrum analysis, there exists C and O elements at the fracture surface resulted from the dregs and oxide films led by casting process, meanwhile, Fe elements is also relatively aggregated in the spokes. The quasi-cleavage plane and dimple morphology are observed in fracture surface, which shows that fracture mechanism is characterized by the ductile-brittle mixed fracture mode, and the crack is propagated along the eutectic region among dendrite cell.
出处
《特种铸造及有色合金》
CAS
CSCD
北大核心
2012年第11期1030-1033,共4页
Special Casting & Nonferrous Alloys
关键词
铝合金轮毂
轮辐
二次枝晶臂间距
拉伸性能
断口分析
Aluminum Alloy Wheels
Spokes
Secondary Dendrite Arm Spacing
Tensile Properties
Fracture Analysis
