Effects of Si content and gas dissolution on shrinkage morphology of hypoeutectic Al-Si alloys.

Abstract

alloys vacuum degassed and gas enriched were cast into conical shell molds. The castings having different quantities of gas porosities show nearly the same total shrinkage volume which decreases at higher Si contents.Pure aluminum and Al-10%Si alloy permit an unchanged volume of external shrinkage and reduced volumes of internal shrinkage with an increase in porosity volume. Al-4%Si and Al-7%Si alloys permit unchanged volumes of internal and external shrinkages respectively at lower and higher porosity levels. The volumes of internal shrinkage at higher porosity levels and of external one at lower porosity levels decrease with an increase in porosity volume. The porosity changes from a concentrated type to dispersed one with an increase in porosity volume. The gas dissolved in the melt has remarkable effects on the shrinkage morphology.

Effect of Al 6061 Alloy Compositions on Mechanical Properties of the Automotive Steering Knuckle Made by Novel Casting Process

“…The mechanical properties of the fabricated steering knuckles are sufficient to satisfy the minimum customer specifications (tensile strength of 290 MPa and an elongation percentage of 8%) and are markedly superior to previously reported examples [26] that had corresponding tensile strengths and elongation percentage of 305 MPa and 7.8%, 334 MPa and 14.3%, and 345 MPa and 11% [26,27]. Therefore, the results reported in this study prove the TAC's ability to produce commercial-grade vehicle components [24]. TAC's applicability was confirmed by the outstanding mechanical properties of the steering knuckles that it produced.…”

“…The porosity in alloys B and C (to which Zr was added) increased as the melt temperature increased from 1003 K to 1063 K, whereas the porosity in alloys D and E (with Zn and Cu added) decreased, as shown in Figure 6. The shrinkage volume of the alloys exhibited the opposite trend as the melt temperature increased (i.e., the shrinkage volume of alloys B and C decreased, whereas those of alloys D and E increased) because the sum of the porosity and shrinkage volume of an alloy is fixed, while the processing conditions vary [24]. Based on this analysis of porosity and shrinkage volume, alloy D and a melt temperature of 1033 K were selected as the composition and condition for TAC fabrication of steering knuckle preforms.…”

“…Additionally, this alloy led to castings with less porosity. The mechanical property of the steering knuckles cast by TAC using the optimized melt was further improved by optimizing the conditions for solution treatment and aging [24].…”

Study of Anodic Film’s Surface and Hardness on A356 Aluminum Alloys, Using Scanning Electron Microscope and In-Situ Nanoindentation

“…The application of Al 2 O 3 -reinforced aluminum alloy matrix composites in the automotive and aircraft industries is gradually increasing for pistons, cylinder heads, and connecting rods [2]. In the case of pure Al-Si alloy, if the Si concentration is lower than 12.6 wt.%, both Al dendrites and eutectic phase may be present in the microstructure [3]. Depending on the concentration of Si, Al-Si alloys can be classified into hypoeutectic alloy (Si < 12.6 wt.%), eutectic alloy (12.6 wt.% Si), and hypereutectic alloy (Si > 12.6 wt.%).…”

“…Depending on the concentration of Si, Al-Si alloys can be classified into hypoeutectic alloy (Si < 12.6 wt.%), eutectic alloy (12.6 wt.% Si), and hypereutectic alloy (Si > 12.6 wt.%). Si content of Al-Si alloys is responsible for shrinkage and thus improving Al castability [3,4]. The Al-Si alloy may contain other elements such as Mg, Cu, and Fe, for which the eutectic phase may be more complex, containing other intermetallic particles.…”