【摘要】 对塑料超声焊接头熔化状态影响其质量的因素进行了研究．通过对焊接接头熔融体温度、粘度、剪切速率等材料物理参数的测试分析发现，焊接压力和振幅对接头熔化层的尺寸及流动状态影响很大，随焊接振幅和焊接压力的增大，塑料熔融体的温度提高，粘度减小，熔化层的厚度而减小．利用光学显微镜观察了接头的组织形貌，发现接头熔化层组织具有明显的熔体流动方向性，焊接振幅和焊接压力越大，熔体剪切速率越大，接头熔化层内组织取向越明显．接头剪切和弯曲强度的测试结果表明，接头力学性能具有明显的各向异性，为获得合适熔化层厚度和组织取向程度，必须合理选取焊接工艺规范，这样才能取得满意焊接接头质量．更多还原

【Abstract】 Factors that affect the quality of ultrasonically welded joints were investigated from point of view of their melting states. Physical parameters such as the temperature, viscosity and thickness of melting layer of plastic material joints were measured and analyzed. Results show that the temperature increases, the viscosity decreases, the thickness of melting layer decreases, with the increasing of welding vibration amplitude and pressure. The microstructure of weld fusion zone was observed by using optical microscope. It is also found that there is strong orientation along transverse direction in the microstructure of the fusion zone, and the tendency of the microstructure orientation increases with the shearing rate. Testing results show that welded joints possess obviously anisotropic mechanics performance, strongly affected by the thickness of melting layer and the degree of orientation. Welding process should be rationally determined to achieve appropriate thickness of melting layer and degree of microstructure orientation for satisfactory performance of welded joints.更多还原