The heat treatment process is important to conduct on A356 Aluminum Alloy that broadly used in an automotive application. Analysis of the effect grain refinement, eutectic silicon modification of T6 solutionizing heat treatment parameter on strength development of A356 Aluminum Alloy were performed to become an important prospect of controlling the behaviour of materials as well as duration and temperature. In this study, there are three parameters condition were conducted which is duration Time (Hour) and Temperature (°C) which is 465°C in 8 hours, 500°C in 7 hours and 535°C in 6 hours, respectively. The study generated three responses that are tensile, hardness test and microstructure analysis of the different temperature and duration time, respectively following by water-quenching. The result showed that the modification of duration time and high temperature of solutionizing heat treatment have superior mechanical properties while the microstructure analysis showed the clear formation of refinement α-Al dendrite and eutectic silicon particle.

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Modelling and optimisation of sand-casting process have been widely studied in casting research. The present study was developed to compare the four types of mathematical model and find the best model used in the optimised process. The four types of mathematical model discussed in this paper were multiple linear regression model, full factorial model, fractional factorial model and response surface methodology model. The best model will used for the optimized process using soft computing technique. The input parameters of these models were silica sand, bentonite, water and coal dust. Meanwhile, permeability was the model output. The four types of mathematical model produced were statistically validated to test for model adequacy by using ANOVA and coefficient of determination. Each model was finally, validated by using mean square error (MSE) and root square error (RMSE). The research findings proved that respond surface methodology model was the best model as compared the other models, which was significant with p-values of less than 0.05. The model also produced the smallest MSE.

Thixoforming is a type of semisolid metal (SSM) processing for forming alloys in the semisolid state to near net-shaped products. In the present study, the effect of a thixoforming process on the microstructure and mechanical properties of Al-6Si-3Cu aluminium alloy was investigated. Melt was poured on a cooling slope at 630oC and the samples were obtained through permanent mold casting. They were thixoformed using a hydraulic press after holding at 571oC for 5min to yield a microstructure predominantly composed of α-Al globules and inter-globular Si particles. As-cast and thixoformed samples were characterized using optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) as well as hardness measurements and tensile tests. The results indicate that the mechanical properties of thixoformed alloy have improved as compared to permanent mold cast alloy. The ultimate tensile strength of as-cast sample was 210 ± 3.5 MPa and increased to 241 ±3.1 MPa in the thixoformed sample while the yield strength of as-cast alloy was 140 ±4.5 MPa and increased to 176±3.3 MPa in the thixoformed sample. The thixoformed alloy also showed an improvement in elongation to fracture as it increased from 2% in as-cast sample to 3.2% in thixoformed alloy. The fracture of as-cast sample showed a cleavage fracture, whereas in the thixoformed alloy, a combination of dimple and cleavage was observed.

Thixoforming is a promising metal forming process to produce near net-shape components with high casting quality. Thixoforming of metallic alloy utilizes the thixotropic behaviour of the material with near globular or globular microstructure in the semi-solid condition. The solid content is between 50% to 70% before forming. In this paper, the effect of plunger speed and a solid fraction on an alternator housing was investigated by advance casting simulation software. The 3D CAD model of the alternator housing was created using SolidWorks software and AnyCasting software is utilized for the simulation of the thixoforming parameter and magnesium alloy (AZ91D) is the material used. The simulation had been done by varying the plunger speed, temperature (solid fraction) of the material, and both Power Law and Bingham Viscosity model are used in the simulation to identify the defect prediction at the end. The simulation result shows that laminar filling in semi-solid slurry able to achieved by controlling the plunger speed and temperature. Slower speed and lower melt temperatures are preferable in thixoforming. Therefore, a solid fraction of the material, plunger speed, and solidification rate do influence the filling behaviour of the casting of semi-solid metal.