Evaluation on Mechanical Properties of Coated RHA-TIO2-LM24 Aluminium Alloy Composite

In the present research work, liquid state technique is employed to prepare the LM4/RHA/TiO2 composites containing four different mass proportion of RHA and TiO2. The weight proportion of reinforcements ie RHA-1,3&5 and TiO2 2,5&6 respectively. Hybrid composite with 3% of RHA and 6% of TiO2 showed the maximum Tensile strength of 298.37 N/mm².It is found that there is 37 % increase of tensile strength while addition of RHA and TiO2 to LM 24.The aluminium based particulate reinforced composite, the dislocations are generated during solutionizing due to thermal mismatch between the matrix and the ceramic reinforcement particles. It can be inferred that the tensile strength increased with an increase in the weight percentage of rice husk ash and TiO2. Because, the RHA particles act as barriers to the dislocations when taking up the load applied. It has been observed that with changing rate of TiO2 compressive quality increments from 478.83 to 653.79 MPa. The increase in compressive strength is mainly due to the decrease in the inter-particle spacing between the particulates since RHA and TiO2 are much harder than LM24. The presence of RHA and TiO2 resists deforming stresses and thus enhancing the compressive strength of the composite material. The maximum hardness value obtained for 5 wt.% of RHA and 6 wt.% of TiO2 .ie.117 BHN. It was observed that the hardness of the composite linearly increasing with the increase in weight fraction of the rice husk ash particles. This occurs due to increases in surface area of the matrix and thus the grain sizes are reduced. The presence of such hard surface area offers more resistance to plastic deformation which leads to increase hardness.. Keywords: LM4/RHA/TiO2, Tensile testing, Compression, Hardness, Rice husk.