Evaluating the Effect of Hot‐Rolling Reduction on the Mechanical Properties of In Situ Formed Aluminum–Magnesium–Silicon (Al‐Mg₂Si) Composites

Abstract

The effects of hot rolling on the microstructure and mechanical properties of as‐cast Al‐15Mg2Si, Al‐20Mg2Si, and modified Al‐15Mg2Si in situ composites are studied. During rolling, the primary and eutectic Mg2Si particles undergo mechanical fragmentation and move along the rolling direction, which results in the enhancement of ductility of the composite compared to the as‐cast state. At high reductions in thickness, however, severely elongated grains and some cracks are observed in the matrix, which are related to the retardation effect of the widely dispersed particles and also fast cooling of sheets during rolling. These effects are found to be responsible for the observed high tensile strength and low ductility of heavily rolled sheets. It is revealed that the strength–ductility balance of the hot‐rolled sheets, as measured by the tensile toughness, is inferior compared to that of the commercially pure Al sheet as the basis for comparison. Therefore, relatively low reductions in thickness are recommended for processing of these composites. The hot extrusion of these composites is also briefly discussed, and it is characterized as a viable route for processing of these composites to achieve high tensile strength with acceptable ductility.

Microstructures and mechanical performance of Mg–4Si–6Ni–xY in situ composite after extrusion process

“…As shown in Figure 8(a,b), in the cast state, the addition of yttrium to the base composite considerably develops the tensile performance, so that the addition of 0.9 wt-% Y results in UTS enhancement (more than 33%) and improved elongation per cent (up to about 90%). Among the predominant reasons that explain the enhancement of the tensile properties, structural modifications such as the refinement of the secondary phases and dendritic structures and the conversion of phases with sharp edges to more spherical ones are very important [47]. The improvement of tensile properties in the cast state can be connected to the modifier's effects on the size and volume fraction of the secondary phases and the development of a uniform structure, as seen in Figure 5.…”

Microstructure Control and Performance Evolution of Hypereutectic Al–20Mg2Si Alloy by Novel Al–Ca–Sb Masteralloy

“…At present, a variety of methods have been studied to improve the microstructure organization of metallic alloys including chemical modifiers, [ 8 ] mechanical methods, [ 9,10 ] and heat treatment. [ 11 ] Yadav et al [ 12 ] used the cooling slope casting technique to cast A319–4 wt%Mg 2 Si composites and found that Mg 2 Si particles were remarkably refined and uniformly dispersed in the matrix, which contributed to the improvement of mechanical properties including hardness and tensile strength.…”

Dry and Lubrication Sliding Wear Characteristics and Wear Mechanism Mapping for In Situ Al–25Mg2Si Composites

“…[4][5][6] It is regarded as a promising candidate for fulfilling the demanding criteria for exceptional mechanical and tribological properties within the automotive and aviation industries. [7][8][9] Consequently, the composites can be a candidate material used in the manufacturing of various automotive parts, including pistons, cylinder liners, connecting rods, cylinder blocks, and brake drums/rotors that are subject to sliding wear with their counterbodies during operation. [10,11] Al-Mg 2 Si composites can be fabricated using either in situ or ex situ techniques.…”

“…[ 4–6 ] It is regarded as a promising candidate for fulfilling the demanding criteria for exceptional mechanical and tribological properties within the automotive and aviation industries. [ 7–9 ]…”