Optimization of dry sliding wear parameters of thixoformed A356-5TiB2in-situ composites using RSM

Abstract

The present investigation is primarily aimed to examine the dry sliding wear behavior of in-situ formed TiB2 composites fabricated by cooling slope casting and thixoforging thereafter. Design of Experiments using central composite design is adapted to optimize the dry sliding wear parameters such as applied load, sliding speed and sliding distance. The responses considered for the analysis are wear rate and coefficient of friction. The wear surface topography and wear debris were characterized by Scanning Electron Microscope and analyzed. The results show that wear rate is significantly influenced by TiB2 particles in the matrix A356 alloy. It is noted that the thixoformed composites show better wear resistance than gravity cast A356 alloy. Moreover, TiB2 particles lower the coefficient of friction when reinforced in A356 alloy, in both gravity cast and thixoformed conditions. The wear rate in the thixoformed composite is reduced by 48% as compared to gravity cast alloy. The improvement in wear resistance in the present composite is not only due to the presence of fine TiB2 particles but also due to thixoforging. Thus, this work is an attempt to optimize the wear parameters of thixoformed A356-5TiB2 in-situ composites.