EFFECT OF MAGNESIUM ENHANCEMENT ON MECHANICAL PROPERTY AND WEAR BEHAVIOUR OF LM6 ALUMINUM ALLOY
For last several decades aluminium and aluminium alloys are widely used in automotive industries because for their favourable properties like low density (about 2700 Kg/m 3 ), good malleability, high formability, high corrosion resistance and high electrical and thermal conductivity. High machinability and workability of aluminium alloys are prone to porosity due to gases dissolved during melting processes. However, in the engineering application pure aluminium and its alloys still have some problems such as relatively low strength, unstable mechanical properties and low wear resistance. The microstructure can be modified and mechanical properties, wear resistance can be improved by alloying, cold working and heat treatment. In this regards, the present paper reports the influences of enhancement of magnesium contents on the mechanical properties and wear behavior of LM 6 aluminum alloy. Index Terms: LM 6 Aluminum alloy, wear rate 1. Introduction: Aluminium and aluminium alloy are gaining huge industrial significance because of their outstanding combination of mechanical, physical and tribological properties over the base alloys. These properties include high specific strength, high wear and seizure resistance, high stiffness, better elevated temperature strength, controlled thermal expansion coefficient and improved damping capacity (1). These properties obtained through addition of alloying elements, cold working and heat treatment. Alloying elements are selected based on their effects and suitability. For the purpose of understanding their effects and importance, alloying elements for majority of alloys are best classified as major and minor elements, microstructure modifiers or impurities, however the impurity elements in some alloys might be major elements in others (2). LM6 is one of the most important Aluminium alloy falls under Aluminium - Silicon alloying system in which aluminium is the predominant metal and high levels of silicon (4% to 13%) are added that contributes to give good casting characteristics and increases fluidity, by which we can produce castings of thick as well as thin sections according to the required design. Other typical alloying elements are Copper, Magnesium, Manganese, Silicon, Zinc, Iron, Nickel, Lead and Tin.
A Comparative Analysis of Grain Size and Mechanical Properties of Al-Si Alloy Components Produced by Different Casting Methods
This study was carried out to compare cast microstructures and mechanical properties of aluminium silicon alloy components cast by various means. For this purpose, sand casting, chill casting and squeeze casting methods were used to produce similar articles of the same shape and size from an Al-8%Si alloy. It was observed that the grain size of the microstructures of the cast products increased from those of squeeze casting through chill casting to sand casting. Conversely, the mechanical properties of the cast products improved from those of sand casting through chill casting to squeeze casting. Therefore, squeeze cast products could be used in as cast condition in engineering applications requiring high quality parts while chill castings and sand castings may be used in as cast condition for non-engineering applications or engineering applications requiring less quality parts.
Influence of experimental parameters on the erosive–corrosive wear of Al–SiC particle composite
Abstract The performance of an Al-alloy-based composite reinforced with 10 wt.% SiC particle in erosive–corrosive slurry environment was examined. The slurry consists of equiaxed sand particles of varying proportion (20, 40 and 60 wt.%) of size approximately 100 μm and solution of water, sulphuric acid and hydrochloric acid. The specimens were placed at various angles of inclination (0°, 45° and 90°) with respect to the direction of rotation of the specimens and at different radial distances (35, 55 and 75 mm) in order to assess the effect of these parameters on erosion–corrosion characteristics of composite. It was observed that wear rates increase drastically with increasing angle of inclination, sand concentration in the slurry, and radial distance. However, it was noticed that the wear rate remains unchanged when the specimen tested in a slurry containing more than 40 wt.% sand and the same become significantly less when the specimen is placed at a radial distance less than 55 mm. Scanning electron microscopic (SEM) study confirms that wear of composite is mainly governed by the synergic effect of the two simultaneous processes: (i) erosion, corrosion and abrasion of the matrix by the slurry; and (ii) fracture and removal of the dispersoid due to particle impingement at high speed. This study also revealed that wear rate at any condition increases to a maximum and then is reduced with the distance traversed. This might be due to work hardening of the specimen surface.