The present paper deals with the study of microstructure and wear characteristics of TiB2 reinforced aluminium metal matrix composites (MMCs). Matrix alloys with 5, 10 and 15% of TiB2 were made using stir casting technique. Effect of sliding velocity on the wear behaviour and tribo-chemistry of the worn surfaces of both matrix and composites sliding against a EN24 steel disc has been investigated under dry conditions. A pin-on-disc wear testing machine was used to find the wear rate, in which EN24 steel disc was used as the counter face, loads of 10-60N in steps of 10N and speeds of 100, 200, 300, 400 and 500 rpm were employed. The results showed that the wear rate was increased with an increase in load and sliding speed for both the materials. However, a lower wear rate was obtained for MMCs when compared to the matrix alloys. The wear transition from slight to severe was presented at the critical applied loads. The transition loads for the MMCs were much higher than that of the matrix alloy. The transition loads were increased with increase in TiB2 and the same was decreased with the increase of sliding speeds. The SEM and EDS analyses were undertaken to demonstrate the effect of TiB2 particles on the wear mechanism for each conditions.

Machining parameters such as speed (v), feed (f) and depth of cut (d) play an important role in determining the residual stress as well as the surface roughness of a material. The material used for the present study is a nickel based super alloy Udiment 720 which finds applications in the manufacture of gas turbine engine components. Residual stress and surface roughness measured on this material showed different magnitudes for different combinations of milling parameters but did not reveal any definite trend. Analytical relationships developed between the magnitudes of residual stress, surface roughness and milling parameters indicated that combined effects of the milling parameters influence both residual stress and surface roughness.

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This paper aims to study the effects of short basalt fiber reinforcement on the mechanical properties of cast aluminium alloy 7075 composites containing short basalt fiber of content ranging from 2.5 to 10 percent by weight in steps of 2.5 percent and fabricated using compo-casting technique. The objective is to investigate the process feasibility and resulting material properties such as young's modulus, ductility, hardness & compression strength. The properties obtained are compared with those of as-cast that were manufactured under the same fabrication conditions. The results of this study revealed that, as the short basalt fiber content was increased, there were significant increases in the ultimate tensile strength, hardness, compressive strength and Young's modulus, accompanied by a reduction in its ductility. Furthermore, the microstructure & facture studies were carried out using Optical Microscopy (OM) and Scanning Electron Microscopy (SEM) in order to establish relationships between the quality of the fiber/aluminium interface bond and hence to link with mechanical properties of the composites.

This paper reports a study of the Coefficient of Thermal Expansion (CTE) of Al7075/basalt short fiber Metal Matrix Composites (MMCs) as a function of temperature and reinforcement. The percentage of reinforcement was varied from 2.5 to 10 wt. % in steps of 2.5% and the composites were prepared by the liquid metallurgy technique. Using Thermal Mechanical Analyzer (TMA) model DuPont 943 equipment, the changes in the linear dimension as a function of temperature is recorded as Percent Linear Change (PLC). The temperature of the tests ranged from 50°C to 300°C in the steps of 5°C both in the heating and cooling cycles. The results show that the CTE significantly increased with increasing temperature but decreased with increasing basalt fiber. These phenomena are explained.Click here and insert your abstract text.