Experimental investigation of the effects of torsion pitch in simultaneous tension-torsion deformation

Commercial pure Al wires are deformed to different torsion pitch by a novel method combining the tension and torsion deformation. An equal channel angular die and a lathe machine are used to apply simultaneous tension-torsion deformation to the initial wires. The amount of induced plastic strain is calculated experimentally after one pass of the deformation. The microstructure of the processed samples is investigated by optical microscopy. The results show that the average grain size of the annealed wire is decreased to 50μm and less than 15μm at the wire center and edge from an initial size of 120μm. The results also revealed a gradient distribution of grain refinement due to torsion deformation. The micro-hardness measurement indicates an increase in hardness of all processed samples. The hardness of annealed sample is increased from 30 HV to 62 HV in the wire center and 73 HV at the wire edge for the sample with 4.8mm torsion pitch. This novel method shows a significant applicability for continuous grain refinement of wires.

Keywords:

Al wires , torsion pitch , properties , tension-torsion