3104铝合金板材不同方向拉伸性能及断裂特征的研究

Study on Tensile Properties and Fracture Characteristic of 3104 Alloy Sheet Along Different Directions

对3104铝合金冷轧板沿轧制方向0°、45°和90°三个方向进行拉伸性能测试,观察断口形貌和显微组织,并分析粗大第二相分布与拉伸方向之间的关系。结果表明,3104铝合金冷轧板材的断口为切变型韧窝断裂特征,裂纹在粗大相自身断裂分离处或者在粗大相尖端处萌生,并在剪切力作用下,以微孔聚合的方式扩展。0°方向拉伸断口韧窝深度最大,延伸率最大;90°方向拉伸断口韧窝深度最小,延伸率最小;而45°方向拉伸断口韧窝深度居中,延伸率也居中。粗大第二相长轴方向和拉伸方向之间的夹角越小,延伸率越大。

The cold roiled sheet of 3104 aluminum alloy was tensile tested along the rolling directions of 0°,45° and 90°, to observe the tensile fracture morphology and microstructure, and analyze the relationship between the coarse second phase particles distribution and tensile direction. The results showed that, the tensile fracture morphology had the characteristic of shear and dimple fracture. The crack initiated from the self-breakage of the coarse second phase particles or the tip of second phase, and propagated in the way of microvoids aggregation under the action of shear force. The depth of dimple in 0~ tensile sample was the largest and the elongation was the highest; the depth of dimple in 90° tensile sample was the smallest and the elongation was the lowest; while the depth of dimple in 45° tensile sam- ple and the elongation were medium. Therefore, the smaller the angle between long axis of coarse second phase and tensile direction, the higher the elongation.