Effective Degassing for Reduced Variability in High-Pressure Die Casting Performance
The reduced solubility of hydrogen in molten aluminium is believed to be a key factor influencing the formation of gas porosity, which adversely affects the mechanical properties. In this study, two crucibles of AlSi10MnMg alloy were degassed using conventional rotary degassing and high shear melt conditioning (HSMC) respectively and then cast into tensile specimens using the high-pressure die casting (HPDC) process. An optimal holding time of 10 min was established for both processing techniques corresponding to reduced density index (DI) and reduced variation in tensile performance. After rotary degassing, DI values were found to increase with increasing holding times, rising to 4.1% after 70 min. For HSMC, a quasi-steady state was observed with a maximum DI value of 1.4% after 190 min. The pore size in HPDC cast specimens was observed to be considerably lower after degassing with the HSMC device compared with rotary degassing.
The authors acknowledge the financial support provided by the Engineering and Physical Sciences Research Council (EPSRC). The authors sincerely thank Dr. Kun Dou for producing simulations aiding in the research.
- 1.J.B. Patel, J.L. Nebreda, and Z. Fan, in Proceedings of 6th Decenn. International Conference on Solidification Processing (Old Windsor, 2017).Google Scholar
- 2.J. Davis, ASM Int. 3, 784 (1993).Google Scholar
- 16.Fiji/ImageJ, https://imagej.nih.gov/ij/. Last accessed 23 Aug 18.
- 17.Rheinhfelden, CAR DS-Mould Des. 1 (2015).Google Scholar
- 19.J. Campbell, Castings, 2nd ed. (Oxford: Butterworth-Heinemann, 2003).Google Scholar