A Study on Mechanical Properties of Fly Ash and Alumina Reinforced Aluminium Alloy (LM25) Composites.

Abstract

The results of an experimental investigation of the mechanical properties of fly ash and Alumina reinforced aluminium alloy (LM25) composites samples, processed by stir casting route are reported in this paper. Three sets of composites with constant weight fraction of fly ash (particle size of 3-100 μm) and Al2O3(particle size of 150 μm) with different wt% were used. Composite samples have the reinforcement weight fractions of constant 3% fly Ash and varying %wt of 5, 10 and 15% Al2O3 . The main mechanical properties studied were the tensile strength,ductilityimpact strength & hardness. Unreinforced LM25 samples were also tested for the same properties. It was found that the tensile strength & hardness of the aluminium alloy (Lm25) composites increases with the increase in %wt of Al2O3 upto certain limit. in addition of more amount of reinforcement the Tensile strength decrease due to poor wettability of the reinforced material with metal aluminium matrix .And the charpy test shows decrease in impact load absorption with increase in %weight reinforcement.The Microstructure study of the samples indicated near uniform distribution of the fly ash and Al2O3 particles in the matrix. LM25 alloy is mainly used where good mechanical properties are required in castings of a shape or dimensions requiring an alloy of excellent castability in order to achieve the desired standard of soundness.The alloy is also used where resistance to corrosion is an important consideration particularly where highstrength is also required.