Influence of intermetallics and element concentrations on the performance of the heat treated HVDC AlSiMgMnCu alloys at nano-scale

作者：Liu, Fei; Qin, Jun; Zhao, Haidong^*; Jiang, Yuanhang; Zheng, Huiting; Chen, Bo^*

来源：MATERIALS & DESIGN, 2023, 229: 111902.

DOI：10.1016/j.matdes.2023.111902

• High vacuum die casting (HVDC)
• SBFSEM
• Element concentrations
• Mechanical properties
• Heat treatment

A method to calculate element concentrations in Al alloy castings, based on the serial block-face scanning electron microscopy (SBFSEM) measurement at nano-scale, was proposed. For the high vacuum die casting (HVDC) Al-10Si-0.4MgMn-0.6Cu alloy, it reveals that the solute fractions of the Si, Mg and Cu in the Al matrix reaches about 0.39 wt%, 0.15 wt%, and 0.10 wt%, respectively, under the as-cast condition. After it was heat treated via T5 process, larger nano-scale precipitation phases with low density and non-uniform distribution were formed in the a-Al matrix. After T6-treated, the narrow neck regions of the seaweed like a-Fe phase particles were fragmented as well, but could not dissolve into the a-Al matrix. The element concentrations of the Si, Mg and Cu in the a-Al matrix increases to 0.75 wt%, 0.23 wt%, and 0.43 wt %, respectively. Hence, finer nano-scale precipitation phases with high density and uniform distribution are formed in the Al matrix. Consequently, the ultimate tensile strength, yield strength and elongation of the T6-treated alloy simultaneously increase of about 15%, 52% and 63%, respectively. It presents that the solute solution during high pressure die casting solidification has decisive effect on the mechanical properties before and after heat treatment.& COPY; 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).

• 单位
  上海交通大学; 同济大学; 1