Effect of Porosity on the Mechanical Properties of Die cast Aluminum Engine Block
Casting defects especially porosity in Aluminum alloy engine block plays a major role in determining the mechanical properties. To investigate the approximate content of porosity and to compare their mechanical properties, an experimental study was carried out on the samples taken from thick and thin sections of an Al 384.1 engine block. The section thicknesses of thick and thin sections were 20 mm and 5 mm, respectively. Mechanical testing of these samples was carried out to show the effect of section thickness on ductility and ultimate strength. It was found that thin sections have higher UTS and ductility as compare to thick sections The three-dimensional porosity of the engine block was analyzed through CT scan. Volumetric porosity for thin sections was lesser within the range of 0.0875% to 0.15%, while that for the thick sections it was within the range of 0.24% to 0.35%.
2. D. Manas and M. Makhlouf, “Effect of key alloying elements onthe feeding characteristics of aluminum-silicon casting alloys,” Journals of light metals, vol. 1, pp. 251–265, 2011.
3. Dashan Sui, Zhenshan Cui, Rong Wang, Shengfei Hao and Qingyou Han, “Effect of cooling process on prsity in the aluminum alloy automotive wheel during low-pressure die casting,” International journal of metalcasting, Nov. 2015, pp. 1-11.
4. I. Boromei, L. Ceschini, L. Morri, A. Morri, G. Nicoletto, and E. Riva, “Influence of the solidification microstructure and porosity on the fatigue strength of al-si-mg casting alloys,” Metallurgical science and Technology, vol. 28, no. 2, pp. 18–24, 2010.
5. L. Dobrzanski, M. Krupinsk, and B. Krupinska, “Structure analysis of al cast alloys,” Journal of Achievements in Materials and Manufacturing Engineering, vol. 27, no. 1, pp. 23–26, 2008.
6. H. Ye, “An overview of the development of al-si-alloy based material for engine applications,” Journal of Material Engineering and Performance, vol. 12, no. 3, pp. 288–297, 2003.
7. J. Campbell, Castings, 2nd ed. Elsevier, 2005.
8. S. Akhter, L. Arnberg, M. Di Sabatino, D. Dispinar and M. Syvertsen “A comparative study of porosity and pore morphology in a directionally solidified A356 alloy, International journal of metalcasting, winter 2009, pp 39-52.
9. D. V.Neff, “Practices for improving metal quality for high pressure die casting,” The North America Die Casting Association, vol. 53, no. 1, pp. 28–31, January 2009.
10. G. J. Kaufman and E. L.Rooy, “Aluminum alloy castings: Properties, processes and applications,” ASM, pp. 47–54, 2004.
11. O. Lashkari, L. Yao, S. Cockcroft, and D. Maijer, “x-ray microtomographic characterization of porosity in aluminum alloy a356,” Metall. Mater. Trans. A: physical metallurgy and materials science, vol. 4, no. 4, pp. 991–999, 2009.
12. H. P.Wang, L. Zhao, B. Zhou, H. Liao, and Y. Pan, “Effect of hydrogen content and cooling rate on porosity in aluminum alloy parts by counter-gravity casting,” Zhuzao/foundry, vol. 58, no. 03, pp. 205–209, 2009.
13. P. Anyalebechi, “Invistigation of the effects of solidification rate and melt hydrogen concentration on porosity formation in aluminum alloy 2024,” in EPD congress 2011-TMS annual meeting and exhibition, vol. 2, 2011, pp. 659–677.
14. J. G. Conley, J. Huang, J. Asada, and K. Akiba, “Modelling the effects of cooling rate, hydrogen content, grain refiners and modifier on microporosity formation in al a356 alloys,” Material Science and Engineering A, vol. 285, pp. 49–55, 2000.
15. S. Shabestari and H. Moemeni, “Effect of copper and solidification conditions on the microstructure and mechanical properties of alsi-mg alloys,” Journal of Materials Processing Technology, vol. 153-154, no. 0, pp. 193–198, 2004, proceedings of the International Conference in Advances in Materials and Processing Technologies.
16. C. Caceres, J. Griffiths, A. Pakdel, and C. Davidson, “Microhardness mapping and the hardness-yield strength relationship in high-pressure diecast magnesium alloy az91,” Materials Science and Engineering: A, vol. 402, no. 1-2, pp. 258–268, 2005.
17. C. D. Lee, “Effects of microporosity on tensile properties of a356 aluminum alloy,” Materials Science and Engineering: A, vol. 464, no. 1-2, pp. 249–254, 2007.
18. Leo, D. Prakash, D. Regener, and W. J. J. Vorster, “Effect of position on the tensile properties in high-pressure die cast mg alloy,” Journal of Alloys and Compound, vol. 470, pp. 111–116, 2009.
19. M. Y. Hu, J. J. Cai, W. L. Sun, H. Y. Jiang, Y. Y. Sang and J. T. Liu, “Diecasting simulation and process ptimization of an A356 aluminum alloy polishing plate,” International journal of metal casting, April 2016, pp. 1-7.
20. Fabio Grosselle, Giulio Timelli, Franco Bonollo, Roberto Molina, “Correlation between microstructure and mechanical properties of Al-Si diecast engine blocks, Metallurgical science and technology, vol. 27-2, 2009, pp. 2-10.
21. S. G. Lee and A. M. Gokhale, “Visualization of the threedimensional pore morphologies in a high pressure die-cast mgal-re alloy,” Scripta Materialia, vol. 56, pp. 501–504, 2007.
22. H. D. Zhao, F. Wang, Y. Li, and W. Xia, “Experimental and numerical analysis of gas entrapment defects in plate adc 12 die casting,” Journal of Materials Processing Technology, vol. 209, no. 9, pp. 4537–4542, May 2009.
23. G. Sigworth, “Understanding quality in aluminum casting,” international journal of metalcasting, pp. 7-22, winter 2011.
24. A. P. Boeira, I. L. Ferreira, and A. Garcia, “Alloy composition and metal/mold heat transfer efficiency affecting inverse segregation and porosity of as-cast al-cu alloys,” Materials & Design, vol. 30, no. 6, pp. 2090 – 2098, 2009.
25. M. A. Irfan, D. Schwam, A. Karve, and R. Ryder, “Porosity reduction and mechanical properties improvement in die cast engine blocks,” Materials Science and Engineering: A, vol. 535, no. 0, pp. 108 – 114, 2012.
26. S. Akhter and L. Arnberg, “A comparative study of porosity and pore morphology in the directionally solidified A356 alloy,” International journal of Metalcasting, pp. 39-52, winter 2009.
27. Anton du Plessis, Stephan Rerhard le Roux, Anina Guelpa, “The CT scanner facility at Stellenbosch University: An open access X-ray computed tomography laboratory, Nuclear instruments and methods in Physics research, vol. 385 B, pp. 42-49, 2016.
28. F. AlMufadi and M. A. Irfan, “Effect of cooling rates on the three dimensional porosity in permanent mold castings measured by computed tomography,” Materials Evaluation, 2014.