Jaya Algorithm for Optimization of Cooling Slope Casting Process Parameters

This study proposed the Jaya algorithm to estimate an improved value of billet performance through the cooling casting process. Jaya algorithm is a recent evolution-based algorithm that simulates using stochastic behaviour. The algorithm concept is the solution obtained for a given problem should move towards the best solution and should avoid the worst solution. This algorithm requires only the common control parameters and does not require any algorithm specific control parameters. To the best our knowledge, Jaya algorithm is not yet been used computational approach for optimization practice, particularly in the Cooling casting process. Three Cooling slope parameters process that influences the billet performance measurements, a maximum degree of sphericity and minimum grain size are pouring temperature, slanting angle, and travelling distance. The results show that the Jaya algorithm gave a better optimal solution for the maximum degree of sphericity and minimum particle size than experimental data.

Producing non-dendritic A356 and A380 feedstocks: Evaluation of the effects of cooling slope casting parameters

In this study, low superheat casting and cooling slope casting processes were carried out with A356 and A380 aluminum alloys in order to obtain feedstocks with near globular microstructures. Castings were conducted at 20 °C above of the liquidus temperature for both processes and molten alloys were cast through a copper cooling slope with two different lengths (350 mm and 650 mm) and two different tilt angles (30° and 60°). In order to evaluate the significance of boron nitride coating on cooling slope, castings in short slope were carried out under both coated and uncoated conditions. Microstructural examinations and hardness measurements were carried out. According to obtained results, cooling slope casting caused superior microstructural properties as compared to low superheat casting, especially for A356 alloy. 30° tilt angle was found more efficient in order to obtain a more globular microstructure for A356, while, on the other hand, the tilt angle of 60° was detected more favorable in that manner for A380. Obtained grain size measurements were slightly improved with the employment of short slope and coating was found beneficial especially for A356 alloy. The measured hardness values did not display any significant difference in the same alloy type except in the low superheat cast A356 specimen, which was obtained with coarser microstructure.

Microstructural Evaluation and Corrosion Resistance of Semisolid Cast A356 Alloy Processed by Equal Channel Angular Pressing

As-cast and semisolid casting using a cooling slope A356 alloy were processed by equal channel angular pressing (ECAP) for Si and grain refinement. The ECAP was conducted at room temperature in a mold, with a channel angle of 120°, and this resulted in a significant size reduction of grain and Si particles from 170.5 and 4.22 to 23.12 and 0.71 µm, respectively, after six passes of heat-treated cooling slope casting, using the ECAP process. The hardness increased with ECAP processing, from 61 HV, for the as-cast alloy, to 134 Hv, after six passes of heat-treated cooling slope casting. The corrosion resistance of the alloy improved, from 0.042 to 0.0012 mmy−1, after the ECAP process. In this work both the strength and corrosion resistance of the ECAPed A356 alloys were improved with the application of the cooling slope process than without (i.e., from the as-cast condition).

MICROSTRUCTURAL INVESTIGATION AND MECHANICAL PROPERTIES OF THIXOFORMED AL-6SI-XCU-0.3MG ALLOYS

In this study, the effect of different amounts of copper (CU) on the microstructure and mechanical properties of thixoformed Al-6Si-xCu-0.3Mg (x= 3, 4 and 5, mass fraction, %) were investigated. The alloys were prepared via cooling slope casting technique, before there were thixoformed using compression press. All of the alloys were then characterized using optical microscope (OM), scanning electron microscope (SEM) and energy dispersive X-ray (EDX). The results obtained revealed that cooling slope casting produced a non-dendritic microstructure and the intermetallic phase in the thixoformed samples was refined and evenly distributed. The results also revealed that as the Cu content in the alloy increases, the hardness and tensile strength of the thixoformed alloys also increase. The hardness of thixoformed Al-6Si-3Cu was 104.1 HV while the hardness of Al-6Si-5Cu alloy was increased to 118.2 HV. The ultimate tensile strength, yield strength and elongation to fracture of the thixoformed alloy which contained 3wt.% Cu were 241 MPa, 176 MPa and 3.2% respectively. The ultimate tensile strength, yield strength and elongation to fracture of the alloy that contained 6wt.% of Cu were 280 MPa, 238 MPa and 1.2% respectively. The fracture surface of the tensile sample with lower Cu content exhibited dimple rupture while higher Cu content showed a cleavage fracture.