ADVANCED MATERIALS & PROCESSES | JULY/AUGUST 2024 32 both the thixomolded and TTMP states (see Table 4). Thus, it is attractive for aerospace and electric vehicle applications. Roll Bonding. Stacked thixomolded sheets are amenable to roll bonding (see Table 5). A 16-layer Mg/Nb composite has been roll bonded, with 150 nanometer layer thicknesses[7]. CONCLUSIONS Thixomolding’s technical virtues, environmental cleanliness/safety advan- tages, 3D net shaping, and high yields (and serendipity) drove its commercial growth. Continued serendipity and the skills of licensees/producers will drive further growth of applications. ~AM&P Note: Thixomolding is a registered trademark of Thixomat Inc. with blends of AM60 and AZ91 wherein tensile properties followed the rule of mixtures[5], see Table 3. Additionally, AZ91, AM60, and ZA12/4 have been blended to produce ZA65 with excellent TTMP properties. Other process developments include a) hopper pre-heating of the chipped feed stock to cut cycle time; b) argon protection in the barrel; and c) materials selection and design of components of the thixomolder to extend life. Special Thixomolded Alloy. AJX810 was developed with Dead Sea Magnesium as sponsored by the Bird Foundation. This Mg-8 % Al alloy with 1% Ca and 0.3 % Sr additions offers good moldability, improved corrosion resistance, corrosion fatigue resistance, fire resistance, creep resistance, and fine microstructure[6] in For more information: Raymond F. Decker, Thixomat Inc., 13753 Otterson Ct., Livonia, MI, 48150, 734.261.2800, rdecker @thixomat.com, www.thixomat.com. References 1. T. Berman, et al., Proc. 9th International Conference Magnesium Alloys and Their Application, p 571, 2012. 2. M. Koç, et al., Experimental Investigations into the Deformation Behavior of Thixo-Molded Mg AZ61L Sheet Alloy, Magnesium Technology 2012, doi.org/10.1007/978-3-319-48203-3_73. 3. Z. Chen, et al., The Effect of Thermomechanical Processing on the Tensile, Fatigue, and Creep Behavior of Magnesium Alloy AM60, Metall Mater Trans A, 42, p 1386–1399, 2011, doi.org/ 10.1007/s11661-010-0478-x. 4. V. Miller, et al., Prediction of Magnesium Alloy Formability: The Role of Texture, Magnesium Technology 2016, doi.org/10.1007/978-3-319-48114-2_51. 5. T. Nandy, et al., Microstructure and Properties of Blended Mg− Al Alloys Fabricated by Semisolid Processing, Metall Mater Trans A, 37, p 3725–3736, 2006, doi.org/10.1007/ s11661-006-1066-y. 6. V. Miller and T.M. Pollock, Texture Modification in a Magnesiumaluminum-calcium Alloy During Uniaxial Compression, Metall Mater Trans A, 47, p 1854-1864, 2016, doi.org/10.1007/ s11661-016-3351-8. 7. B. Leu, et al., Processing of Dilute Mg–Zn–Mn–Ca Alloy/Nb Multilayers by Accumulative Roll Bonding, Adv. Eng. Mater., 22, p 1900673, 2020, doi.org/ 10.1002/adem.201900673. BENEFITS OF THIXOMOLDING OVER DIECASTING Advantage Reason Clean environment No SF6, no waste slag and dross disposal Safe environment Melt encased in barrel High yield Short sprue/runners, all scrap recycled Low porosity Semi-solid flow High tensile strength Finer grain size High ductility and formability Low texture, modified dislocation slip system, lower porosity, < 20 nm transition microstructures Lower corrosion rate Finer and well-distributed intermetallics Higher fatigue and corrosion fatigue strength Low porosity, lower corrosion rate Longer die life 80°C lower melt temperature Tighter dimensions 80°C lower melt temperature Thinner sections, down to 0.5 mm Semi-solid flow, short hot sprue/runners Portability Entire thixomolder can be split in two sections and transported to new site and reconnected. (No separate open melting and pouring unit.)
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