Effect of process parameters on surface composite fabrication of newly commercialized Mg-ZE41 alloy by friction stir processing (FSP): microstructural development and microhardness

Abstract

PurposeAltering the microstructure and developing the surface metal matrix composites (MMCs) in a solid-state by friction stir processing (FSP) has been on trend for the past decade. The microstructural modification increases the material properties, which are structure sensitive. The microstructural evolution is highly influenced by the selection of process parameters in FSP. In this study, the effect of process parameters on the microstructure evolution and microhardness of the fabrication of surface MMCs of newly commercialized Mg-ZE41 alloy by the incorporation of different reinforcement particles such as ZrO2, CeO2 and Al2O3 is investigated.Design/methodology/approachBy making use of Taguchi’s design of experimentation, which recognizes the crucial factors and ascertain their effect on the properties of the material, the optimization of process parameters for this study was done using MATLAB-14 software. The parameters were adopted along with the levels throughout the FSP for the fabrication of different surface MMCs. For each reinforcement particle, two factors at three levels each had L9 factorial design were used to analyse the effect of these factors on the processing result (microstructure, grain refinement and hardness). The two different factors used in this study are tool rotational speed (TRS) and tool traverse speed (TTS) as a part of the full factorial design matrix for different surface MMCs.FindingsAmong all combinations, TRS of 1500 rpm and TTS of 20 mm/min. for ZE41-ZrO2 MMCs and ZE41-CeO2 MMCs were observed as optimum to produce defect-free processed zone along with the high level of grain refinement and hardness, whereas for ZE41-Al2O3 the same was obtained at 1500 rpm TRS and 10 mm/min TTS.Originality/valueIn this paper, the role of process parameters in the development of surface MMCs on newly commercialized Mg-ZE41 alloy by FSP is investigated. The effect of TRS and TTS on microstructure evolution, grain refinement and microhardness is analysed. Hence, in this study, the optimum parameters for the fabrication of surface MMCs of Mg-ZE41 alloy have thus been established.