中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 28 No. 5 May 2018 |
（1. School of Metallurgy and Materials Engineering, Iran University of Science and Technology, 16846-13114, Tehran, Iran; 2. Center of Excellence for High Strength Alloys Technology, School of Metallurgy and Materials Engineering, Iran University of Science and Technology, 16846-13114, Tehran, Iran; 3. School of Mechanical Engineering, Iran University of Science and Technology, 16846-13114, Tehran, Iran）
Abstract:Two theoretical criteria represented by Katgerman, and Clyne and Davies for prognosticating hot tearing sensitivity were compared. Both unrefined and grain-refined samples of Al2024 alloy were solidified at various cooling rates ranging from 0.4 to 17.5 °C/s. Thermal analysis was used to detect dendrite coherency point and temperature of eutectic reaction. Curves of solid and liquid fractions were plotted based on Newtonian method to determine hot tearing susceptible areas. The experimental results show that the most susceptible zone in which hot tearing can occur in Al2024 is where Al2CuMg intermetallic compound forms as a eutectic phase at last stage of mushy-state interval. Also, both criteria are in a good agreement with each other at high cooling rates used in direct-chill casting process while Clyne and Davies’ model is more acceptable to determine hot tearing tendency from low to medium cooling rates.
Key words: 2024 aluminum alloy; dendrite coherency; direct-chill casting; thermal analysis; hot tearing
