• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1999.04a
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• pp.26-27
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• 1999

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1996.11a
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• pp.28-28
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• 1996

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1996.11a
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• pp.40-40
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• 1996

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2002.11a
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• pp.43-43
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• 2002

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2005.04a
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• pp.30-30
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• 2005

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1997.04a
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• pp.26-27
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• 1997

• Journal of Technologic Dentistry
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• v.23 no.1
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• pp.9-19
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• 2001

Microstructure and phase transformation of Ti-Ni-Cu alloy powders produced by using attrition milling method were studied. Mixed powders of Ti-(50-X)Ni-XCu ($X=0{\sim}20$ at%) in composition range were mechanically alloyed for maximum 20 hours by using SUS 1/4" ball in argon atmosphere. Ball to powder ratio was 50: 1 and impeller speed was 350rpm. Mechanically alloyed with attrition millimg method. powder was heat treated at the temperature up to $850^{\circ}C$ for 1 hour in the $10^{-6}$ torr vacuum. Ti-Ni-Cu alloy powders have been fabricated by attrition milling method. and then phase transformation behaviours and microstructual properties of the alloy powders were investigated to assist in improving the the high damping capacity of Ti-Ni-Cu shape memory alloy powders. The results obtained are as follows: 1. After heat treating of fully mechanically alloyed powder at $850^{\circ}C$ for 1hour. most of the B2 and B 19' phases was formed and $TiNi_3$ were coexisted. 2. The B 19' martensite were formed in Ti-Ni-Cu alloy powders whose Cu-content is less than 5a/o. where as the B19 martensite in those whose Cu-content is more than 10at%. 3. The powders of as-milled Ti-Ni-Cu alloys whose Cu-contents is less than 5at% are amorphous. whereas those of as-milled Ti-Ni-Cu alloys whose Cu-content is more than 10at% are crystalline. This means that Cu addition tends to suppress amorphization of Ti-Ni alloy powders.

• Journal of Korea Foundry Society
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• v.31 no.1
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• pp.26-30
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• 2011

For the fabrication of bulk near-net-shape Ti-Ni-Cu shape memory alloys, consolidation of Ti-Ni-Cu alloy powders are useful because of their brittle property. In the present study, $Ti_{50}Ni_{30}Cu_{20}$ shape memory alloy powders were prepared by gas atomization and martensitic transformation temperatures and microstructures of those powders were investigated as a function of powder size. The size distribution of the powders was measured by conventional sieving, and sieved powders with the specific size range of 25 to $150\;{\mu}m$ were chosen for this examination. XRD analysis showed that the B2-B19 martensitic transformation occurred in the powders. In DSC curves of the as-atomized $Ti_{50}Ni_{30}Cu_{20}$ powders as a function of powder size, only one clear peak was found on each cooling and heating curve. The martensitic transformation start temperature($M_s$) of the $25-50\;{\mu}m$ powders was $31.5^{\circ}C$. The $M_s$ increased with increasing powder size and the difference of $M_s$ between $25-50\;{\mu}m$ powders and $100-150\;{\mu}m$ powders is only $1^{\circ}C$. The typical microstructure of the rapidly solidified powders showed cellular morphology and very small pores were observed in intercellular regions.

• Journal of Powder Materials
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• v.7 no.2
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• pp.85-92
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• 2000

The Cu55Ti45 system was effectively mechanically-alloyed using a pulverizer. Noncrystallinities of the powders were characterized by TEM, X-ray and DSC. The amorphous powders were consolidated without losing their noncrystallinities. The consolidating conditions keeping a non-crystalline were obtained by building a TTT diagram of the amorphous powders. The microhardness of the crystallite and bulk amorphous alloys are also compared.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1988.10a
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• pp.102-104
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• 1988

GdBa$_2$Cu$_3$Ox superconductors were prepared by ceramic powder compacting method. X-ray powder diffraction patterns and SEM microphotographs were taken to analyze phase and microstructure, and electrical properties were investigated by 4-point probe method. The results show that the $N_2$atmosphere enhances the formation of high Tc(critical temperature) phase, but the Tc is independent of sintering conditions.