TY - GEN
T1 - Production of semi-solid slurry through heterogeneous nucleation in Metal Matrix Nanocomposites (MMNC) using nano-scale ultrasonically dispersed inoculants
AU - De Cicco, Michael
AU - Turng, Lih Sheng
AU - Li, Xiaochun
AU - Perepezko, John H.
PY - 2008
Y1 - 2008
N2 - Ever since copious nucleation was shown to be an efficient, cost effective method for producing semi-solid slurry, many processes have been developed to take advantage of the cost savings inherent in this method of slurry production. Despite great advances in various aspects of semi-solid processing, the cost competitive nature of the industry, most noticeably the auto industry, has prevented a wider adoption of semi-solid casting technology. This research aims to realize a more industrial appealing process by combining the synergistic benefits of semi-solid casting technology with metal matrix nanocomposite (MMNC) technology, thus creating higher value products with superior properties cost-effectively. To do this, a process that produces a semi-solid slurry though the nucleation catalysis induced by nanoparticle additions as small as 1 wt. % to alloys is proposed and the results are presented in this paper. Examination of the potential for nano-scale inoculants to catalyze nucleation of solidification showed that despite their small sizes, inoculants on the scale of tens of nanometers are capable of catalyzing nucleation in the zinc and aluminum alloys studied. Employing the differential scanning calorimetry (DSC), differential thermal analysis (DTA), and droplet emulsion techniques with nanocomposite samples showed a significant reduction in undercooling owing to the homogeneous distribution of nanoparticles by ultrasonic mixing and the potency of those nanoparticles to catalyze nucleation. Comparison of undercoolings between different types of nanoparticles, such as silicon carbide (SiC), gamma and alpha alumina (Al2O3), and titanium carbide (TiC), to relative potencies predicted by minimum lattice disregistry showed a strong correlation. Results were also examined in light of free growth and nucleation controlled grain initiation. For nanoparticles predicted to be potent nucleation catalysts by lattice disregistry, the undercoolings observed fell into the free growth controlled grain initiation regime.
AB - Ever since copious nucleation was shown to be an efficient, cost effective method for producing semi-solid slurry, many processes have been developed to take advantage of the cost savings inherent in this method of slurry production. Despite great advances in various aspects of semi-solid processing, the cost competitive nature of the industry, most noticeably the auto industry, has prevented a wider adoption of semi-solid casting technology. This research aims to realize a more industrial appealing process by combining the synergistic benefits of semi-solid casting technology with metal matrix nanocomposite (MMNC) technology, thus creating higher value products with superior properties cost-effectively. To do this, a process that produces a semi-solid slurry though the nucleation catalysis induced by nanoparticle additions as small as 1 wt. % to alloys is proposed and the results are presented in this paper. Examination of the potential for nano-scale inoculants to catalyze nucleation of solidification showed that despite their small sizes, inoculants on the scale of tens of nanometers are capable of catalyzing nucleation in the zinc and aluminum alloys studied. Employing the differential scanning calorimetry (DSC), differential thermal analysis (DTA), and droplet emulsion techniques with nanocomposite samples showed a significant reduction in undercooling owing to the homogeneous distribution of nanoparticles by ultrasonic mixing and the potency of those nanoparticles to catalyze nucleation. Comparison of undercoolings between different types of nanoparticles, such as silicon carbide (SiC), gamma and alpha alumina (Al2O3), and titanium carbide (TiC), to relative potencies predicted by minimum lattice disregistry showed a strong correlation. Results were also examined in light of free growth and nucleation controlled grain initiation. For nanoparticles predicted to be potent nucleation catalysts by lattice disregistry, the undercoolings observed fell into the free growth controlled grain initiation regime.
KW - Free growth
KW - Metal matrix nanocomposite
KW - Nucleation
KW - Ultrasonic dispersion
UR - http://www.scopus.com/inward/record.url?scp=58049217549&partnerID=8YFLogxK
U2 - 10.4028/www.scientific.net/ssp.141-143.487
DO - 10.4028/www.scientific.net/ssp.141-143.487
M3 - 会议稿件
AN - SCOPUS:58049217549
SN - 9771012039401
T3 - Solid State Phenomena
SP - 487
EP - 492
BT - Semi-Solid Processing of Alloys and Composites X - Selected, peer reviewed papers from the 10th International Conference on Semi-Solid Processing of Alloys and Composites, S2P 2008
PB - Trans Tech Publications Ltd
T2 - Semi-Solid Processing of Alloys and Composites 10 - Selected, peer reviewed papers from the 10th International Conference on Semi-Solid Processing of Alloy and Composites, S2P 2008
Y2 - 16 September 2008 through 18 September 2008
ER -