Effect of pouring and cooling temperatures on microstructures and mechanical properties of as-cast and T6 treated A356 alloy

Abstract

A 356 is a hypoeutectic Al-Si alloy which has been widely used in many industrial fields owing to its good castability, low density, high corrosion resistance, and good weldability [1-3]. The T6 heat treated A356 has often been used in automobile wheel hubs [4-5]. In order to achieve good comprehensive performance, the most common method is adding less than 0.2wt.% of Ti to the Al-Si alloy to refine the grain size and obtain a fine-equiaxed structure. Al 3 Ti and α-Al have similar lattice constants, so the Al 3 Ti particles act as heterogeneous nucleation sites for α-Al grains and refine the microstructure of A356 [6,7]. However, a previous researcher found that the Al 3 Ti particles can only dissolve into liquid alloy at high temperature, which significantly deteriorates its refining effect [8,9]. As it was known, the mechanical properties of A356 are largely dependent on the size and morphology of eutectic Si phase. The T6 heat treatment can help

Magnetic field treatment effects on microstructure and properties of A356 aluminium alloy

“…One such crucial determinant is the degree of subcooling. Additionally, the strength of the magnetic field exerts an influence on the phase transition temperature of alloys, which can be expressed as follows: 9,31 ΔT = T H − T 0 = 1 2 μ 0 (φ old phase χ old phase − φ new phase χ new phase )H 2 1 ΔS 0 (5) where T H is phase transition temperature after applying the pulsed magnetic field; T 0 is the phase transition temperature of ageing without pulsed magnetic field; μ 0 is the magnetic permeability; φ old phase , φ new phase and χ old phase ; χ new phase are the volume fraction and volume magnetisation of the new and old phases, respectively; H is magnetic field strength and ΔS 0 is the entropy of the phase transition. One study 32 illustrates the magnitude of each phase within the precipitation sequence of A356 aluminium alloy (i.e.…”

“…2 Over recent years, various heat treatment processes have been selected to improve alloy's microstructure and properties, incorporating methodologies like solid solution treatment and artificial ageing. [3][4][5] The conventional T6 heat treatment process in both time and energy-intensive. Hence, the primary focus is reforming microstructures to obtain superior mechanical attributes while optimising energy efficiency.…”