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In this paper, solution and ageing heat treatment processes were used to improve microplastic deformation behaviors of as-cast SiCp/AZ61 magnesium metal matrix composites (Mg MMCs) fabricated by stir casting method. Higher percentages of SiC particle reinforcements showed higher microhardness values. Ageing heat treatment process was seen significant on the 12 h aged 2 wt% SiCp/AZ61 Mg MMC which induced lower microhardness value. At the 12 h ageing of 2 wt% SiCp/AZ61 Mg MMC the formations of particle free regions and discontinuous secondary phases were observed. For a higher ageing time, the secondary phases distribution became continuous and laminar structure. The addition of 5 wt% SiC particles resulted in the formation of Mg 2 Si phase throughout the whole heat treatment processes. The addition of SiC particles reinforcements increased the phase heterogeneity during ageing heat treatment processes. XRD patterns revealed the presence of nanocrystalline MgSiO 3 phase on the 12 h aged 2 wt% SiCp/AZ61 Mg MMC. Using reference intensity ration (RIR) method a 51.6% of MgSiO 3 phase was determined which can cause the formation of microplastic deformation behavior. And also, the maximum average crystallite size, compressive microstrain and microcrack-free phase boundaries were observed on the 12 h aged 2 wt% SiCp/AZ61 Mg MMC. [ABSTRACT FROM AUTHOR]

AZ91 reinforced with four different concentrations (0,0.3,0.6,1)wt% of WS 2 micro particles were fabricated using stir casting method. The samples were deformed by equal channel angular pressing (ECAP) after homogenization. The scanning electron microscopy and X-ray diffraction were used to investigate the microstructure and phase composition respectively. The results reveal that rod-like precipitates produced during the homogenization process are refined and bounded in the grain boundaries by the combined effect of WS 2 enrichment and increasing number of passes of ECAP. The needle precipitates are eminent in 1pass 0.3 wt%WS 2 /AZ91. The β-Mg 17 Al 12 and extracted Al particles are dissolved and secondary phases are produced by dynamic recrystallization after 2pass 1 wt%WS 2 /AZ91. The maximum crystallite size and microstrain distribution have been observed for 1pass 0.6 wt%WS 2 /AZ91. The mechanical properties investigation represents that 2pass 0.6 wt%WS 2 /AZ91 has optimal yield strength and ultimate tensile strength. The (22.143)%, (44.735)% and (92) % increment in yield strength, ultimate tensile strength and elongation have been observed in 2pass 1 wt%WS 2 /AZ91 compared with homogenized monolithic AZ91 alloy respectively. The maximum young's modulus (6696.218MPa) has been found for 1pass homogenized WS2/AZ91 and minimum (4108.165MPa) for homogenized 0.6 wt%WS 2 /AZ91. The ECAP deformed 1pass 0.3 wt%WS 2 /AZ91 exhibits the maximum strain hardening rate. The YTS, UTS, and elongation are (30.41) %, (47.6) % and (51.9)% increased after 2pass-0.6 wt%WS 2 /AZ91. [ABSTRACT FROM AUTHOR]