Volume 37, Issue 4 (Journal of Advanced Materials-winter 2019)                   jame 2019, 37(4): 91-100 | Back to browse issues page


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1. Department of Materials Engineering, Isfahan University of Technology, Isfahan, Iran. , m.lashani@ma.iut.ac.ir
Abstract:   (3780 Views)
Mechanical properties of the alloys are a strong function of the average silicon particles size and the secondary dendrite arm spacing (SDAS). Modified Hall-Petch equation expresses the effects of these two microstructural parameters on the yield strength and ultimate tensile strength of the Al-Si based alloys. These microstructural parameters depen on parameters such as chemical composition, cooling rate and melt treatment. In this study, the effect of cooling rate on the  equation constants of the alloy were determined. For this purpose, the alloy was poured at 750 °C in three different molds including a sand mold, a preheated steel mold, and a water cooled steel mold. The Thermal and microstructural analysis showed that the cooling rate in the metal mold was 15.7 times higher than that of the sand mold, which resulted in a decrease of the SDAS from 54 micrometers to 17 micrometers. It was also found that by reducing the SDAS from 45 micrometers to 17 micrometers, the yield strength and tensile strength were increased by 16.5% and 6.5%, respectively. The modified Hall-Petch equation constants and the microstructure-mechanical properties relationships were then established by the microstructural and tensile test studies.
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Type of Study: Research | Subject: Solidification and casting
Received: 2017/01/6 | Accepted: 2018/10/27 | Published: 2019/03/15