钛铝合金板材压印成形及接头力学性能实验研究

对钛合金(TA1)和铝合金(Al5052)板材组合进行压印连接的可行性进行了研究,发现压印连接可以有效地实现TA1-TA1组合和Al5052-TA1组合的连接。对所获得的接头进行准静态力学性能测试,并运用扫描电子显微镜对接头拉伸断口进行微观分析。结果表明,压印连接时,钛合金和铝合金的组合能够获得成形性较好的压印接头,TA1-TA1接头的最大载荷和失效位移较Al5052-TA1接头提高了303.8%和49.4%,这两种接头静态失效形式相似,为上板颈部材料首先被破坏,产生裂纹,之后裂纹沿周向逐渐扩展,最终导致整个压印接头断裂。由微观断口可以判断TAl-TA1接头断口处呈现准解理和韧窝形貌,即同时具有韧性断裂和脆性断裂的特征;Al5052-TA1接头断口处呈现直径和深度较大的拉长韧窝,即为韧性断裂。

Experimental Investigation on Clinching Feasibility and Mechanical Properties of Clinched Joints for Titanium and Aluminum Alloy Sheets

The feasibility of clinching process of titanium alloy (TA1) and aluminum alloy 5052 (Al5052) sheets was investigated, and the inference was that the combinations of TA1-TA1 sheets and Al5052-TA1 sheets could be realized by clinching effectively. The quasi-static tests were conducted for the joints obtained by clinching and the scanning electron microscope (SEM) was adopted to analyze the microstructure of tensile fracture in clinched joint. The results showed that the combinations of TA1-TA1 sheets and Al5052-TA1 sheets could obtain the clinched joints with good formability using clinching technology. Compared with the clinched joints in Al5052-TA1, the peak load and failure displacement of clinched joints in TA1-TA1 was improved by 303.8% and 49.4% respectively. The static failure modes of clinched joints in TA1-TA1 and Al5052-TA1 were similar. The neck materials of upper sheet were broken firstly, generating the cracks, and then the cracks propagated along the circumferential direction, which led to the fracture of joints finally. Microscopic analysis showed that the quasi-cleavage and dimple morphologies located at the fracture of the clinched joints in TAl-TA1 indicated a fracture combined with brittle and ductile fracture characte-ristics. Big and deep dimple morphologies located at the fracture of the clinched joints in Al5052-TA1 demonstrated ductile fracture characteristics.