Preparation and mechanism of copper ultra-fine grain strip by ultrasonic vibration extrusion cutting-model, FEM and experiment

Abstract

Ultra-fine grain materials are widely used due to their superior material properties. In presented work, ultrasonic vibration extrusion cutting (UVEC) is put forward to prepare ultra-fine grain strip. UVEC induces material to produce strain and strain rate far exceeding that of ordinary severe plastic deformation process. The mathematical model and finite element simulation model of physical field parameters was established. UVEC test platform was set up to verify each other with previous model. Relationship and mechanism among processing parameters, physical field parameters and microstructure changes were analyzed, mechanism of grain refinement in UVEC was revealed. The results show that the grain size can be refined to ultra-fine grain size by UVEC method. With the increase of tool rake angle, the strip equivalent strain/equivalent strain rate decrease gradually, and the grain refinement weakens gradually. Besides UVEC, ordinary turning (OT) and ordinary extrusion cutting (OEC) tests are also carried out. The average grain size of UVEC-strip (0.75 μm) is about 3/4 that of OEC-strip (1.03 μm). The passivation layer depth of OT-strip (38 μm), OEC-strip (58 μm) and UVEC-strip (75 μm) increases gradually.

Keywords

• Grain refinement
• Tool rake angle
• Ultrasonic vibration
• Extrusion cutting
• Strip