Effect of Foundry Variables on the Casting Quality of As-Cast LM25 Aluminium Alloy
Mohammad Sharear Kabir1, Ehsan Ahmed Ashrafi2, Tamzid Ibn Minhaj3, Md Moinul Islam4
1Mohammad Sharear Kabir, Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka, Bangladesh.
2Ehsan Ahmed Ashrafi, Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka, Bangladesh.
3Tamzid Ibn Minhaj, Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka, Bangladesh.
4Md Moinul Islam, Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka, Bangladesh.
Manuscript received on July 22, 2014. | Revised Manuscript received on August 14, 2014. | Manuscript published on August 30, 2014. | PP: 46-51 | Volume-3 Issue-6, August 2014. | Retrieval Number: E3145063514/2013©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: The effect of foundry variables, such as mold materials and pouring temperature on the microstructure, dendrite arm spacing, percentage porosity and mechanical properties of as-cast LM25 Al alloy was investigated. The microstructure of the as-cast samples was characterized by optical microscopy. The results showed that the secondary dendrite arm spacing (SDAS, λ) is well refined by pouring at higher temperatures in metal mold compared to greensand mold. The SDAS decreases with increasing pouring temperature due to multiplication of nucleation sites in the superheating liquid melt. The percentage porosity of the cast specimens decreases with increasing pouring temperatures and is lowest for metal mold at highest pouring temperature. The mechanical properties of the as-cast LM25 Al alloy, such as hardness and ultimate tensile strength increases as pouring temperature increases. However, percentage elongation of the as-cast alloy decreases with increasing pouring temperatures. Among the mold materials, permanent metal mold casting has shown to impart better quality than greensand mold casting.
Keywords: LM25 Al alloy, Pouring temperature, Secondary dendrite arm spacing (SDAS, λ), Percentage porosity, Permanent metal mold, Greensand mold, Mechanical property.