Towards understanding the microstructure and temperature rule in large strain extrusion machining

Abstract

Large strain extrusion machining (LSEM) is a typical process for preparing ultrafine or nanocrystalline strips. It is based on large plastic deformation. The processing parameters of LSEM in this study were optimized by experiments and simulations. Using the orthogonal array, signal-to-noise ratio, and analysis of variance, the influence and contribution of processing parameters on response variables were analyzed. Because of the difference in processing parameters between optimizing the average grain size and the maximum temperature, the response variables analyzed must be correctly selected. Furthermore, the optimal processing parameters for obtaining the minimum average grain size and the lowest maximum temperature are analyzed. The results show that the tool rake angle is the most important factor. However, the level of this factor required to achieve the minimum average grain size is different from that required to obtain the lowest maximum temperature. The validity of the method is verified through experiments and simulations.