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Metallurgical and Materials Transactions A

, Volume 27, Issue 12, pp 3983–3991 | Cite as

The quench sensitivity of cast Al-7 wt pct Si-0.4 wt pct Mg alloy

  • D. L. Zhang
  • L. Zheng
Article

Abstract

The effect of quenching condition on the mechanical properties of an A356 (Al-7 wt pct Si-0.4 wt pct Mg) casting alloy has been studied using a combination of mechanical testing, differential scanning calorimetry (DSC), and transmission electron microscopy (TEM). As the quench rate decreases from 250 °C/s to 0.5 °C/s, the ultimate tensile strength (UTS) and yield strength decrease by approximately 27 and 33 pct, respectively. The ductility also decreases with decreasing quench rate. It appears that with the peak-aged condition, both the UTS and yield strength are a logarithmic function of the quench rate,i.e., UTS orσ y =A logR +B. The termA is a measure of quench sensitivity. For both UTS and yield strength of the peak-aged A356 alloy,A is approximately 32 to 33 MPa/log (°C/s). The peak-aged A356 alloy is more quench sensitive than the aluminum alloy 6063. For 6063,A is approximately 10 MPa/log (°C/s). The higher quench sensitivity of A356 is probably due to the high level of excess Si. A lower quench rate results in a lower level of solute supersaturation in the α-Al matrix and a decreased amount of excess Si in the matrix after quenching. Both of these mechanisms play important roles in causing the decrease in the strength of the peak-aged A356 with decreasing the quench rate.

Keywords

Yield Strength Material Transaction Ultimate Tensile Strength Casting Alloy A356 Alloy 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© ASM International & TMS-The Minerals, Metals and Materials Society 1996

Authors and Affiliations

  • D. L. Zhang
    • 1
  • L. Zheng
    • 1
  1. 1.the CRC for Alloy and Solidification Technology (CAST), Department of Mining and Metallurgical EngineeringThe University of QueenslandAustralia

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