The Effect of Inert Gas Injection Semisolid Process on the Structure and Hot Tearing ‎Susceptibility of Al-4.3%Cu Alloy

Document Type : Original Research Article

Authors

1 Ph.D. Student, School of Metallurgy and Materials Engineering, Iran University of Science and Technology

2 Professor, School of Metallurgy and Materials Engineering, Iran University of Science and Technology

3 M.Sc. Graduate., School of Metallurgy and Materials Engineering, Iran University of Science and Technology

10.22034/frj.2019.177399.1077

Abstract

In this investigation Al-4.3% alloy was treated through gas induced semi-solid (GISS) process. The average grain size decreased significantly from several millimeters to less than 100μm through this process. Results showed that GISS changed the structure from fully dendritic to globular morphology. Casting defects such as shrinkage porosities were not detected in the GISS samples. The average grain size decreased when the inert gas flow rate increased. Period time of inert gas injection did not have a significant effect on average grain size. Increasing the staring temperature of gas purging led to an increase in average grain size at constant gas flow rate and gas purging duration. The GISS sample which was prepared through inert gas purging of 20s and having flow rate of 4L.min-1 at 670˚C, had the minimum average grain size (76μm) and maximum sphericity (0.86). According to the results, GISS led to a significant decrease in hot tearing susceptibility from 14 for conventional cast sample to 1 for 680-10S-2L GISS sample. Therefore, high quality castings can be produced using GISS process.

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References

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History

  • Receive Date: 31 March 2019
  • Revise Date: 22 April 2019
  • Accept Date: 01 May 2019

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