Interparticle Bonding of Cu Powder under Repetitive Unidirectional Friction

ABSTRACTThe Dynamic Compaction of powdered materials becomes a particularly attractive technique for consolidating hard materials, because of the ease with which high pressures are achieved, and for metastable materials, because of the possibility of avoiding large-scale, high temperature excursions. The shock-wave conditions necessary for achieving high densities and interparticle bonding are evaluated experimentally. The bonding and melting taking place can be identified by post-consolidation studies, and the inter-relation between compact integrity and melting is shown. An attempt is made to develop a “process window” analogous to that of explosive bonding, to describe the conditions necessary for consolidation. Finally, in view of the necessity for localisation of plastic flow during consolidation, an indication of the influence of material deformation parameters is given.

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Summary of collapsible behaviour of artificially structured loess in oedometer and triaxial wetting tests

Canadian Geotechnical Journal ◽

10.1139/t2012-075 ◽

2012 ◽

Vol 49 (10) ◽

pp. 1147-1157 ◽

Cited By ~ 46

Author(s):

Mingjing Jiang ◽

Haijun Hu ◽

Fang Liu

Keyword(s):

Water Content ◽

Experimental Studies ◽

Stable State ◽

Confining Pressure ◽

Triaxial Apparatus ◽

Stress Point ◽

High Confining Pressure ◽

Interparticle Bonding ◽

Oedometer Tests ◽

Natural Loess

This paper summarizes experimental studies on wetting-induced collapsibility in loess using single-oedometer, double-oedometer, and triaxial wetting tests. Artificially structural loess samples with interparticle bonding calcite (CaCO3) and a large void ratio were tested in the laboratory to avoid sampling disturbance of natural loess. The comparison between the single- and double-oedometer tests confirms that the wetting-induced deformation is independent of the sequence of wetting and loading. The conventional triaxial apparatus was enhanced for investigating the collapse deformation in response to different water content increments when subjected to different stress levels. The wetting-induced strain subjected to high confining pressure develops in two steps. It increases with increasing water content and reaches a relatively stable plateau, and then increases rapidly again until a final stable state is reached. The initial collapse surface was found by plotting the wetting-induced strain vectors observed in triaxial wetting tests. The wetting-induced strain is negligible when a specimen is wetted at a stress point inside this surface, while it becomes significant when wetted beyond this surface.

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Thermal Properties of Various Ti-Al-C Composites Prepared by Hot Shock Compaction Utilizing Combustion Synthesis/ Właściwości Termiczne Kompozytów Ti-Al-C Uzyskanych Z Wykorzystaniem Metody Udarowego Zagęszczania Na Gorąco

Archives of Metallurgy and Materials ◽

10.2478/amm-2014-0267 ◽

2014 ◽

Vol 59 (4) ◽

pp. 1575-1578 ◽

Cited By ~ 4

Author(s):

R. Tomoshige ◽

H. Tanaka

Keyword(s):

Combustion Synthesis ◽

Coefficient Of Thermal Expansion ◽

Max Phase ◽

X Ray Diffraction ◽

X Ray ◽

Shock Compaction ◽

Increasing Temperature ◽

Interparticle Bonding ◽

Compaction Method ◽

Explosive Detonation

Abstract Hot shock compaction method was utilized for the consolidation of MAX phase composites consisting of Ti, Al and C. This paper presents the production of dense, crack-free composites by combining the combustion synthesis with explosive detonation. Another objective is to investigate various properties of the obtained shock-compacts. The shock compacted materials were post-annealed at 1173 K for releasing the shock-induced strain. As a result, these compacts had strong interparticle bonding strength and few macro cracks. Intermetallic compounds (TiAl, Ti2Al and Ti3Al) and non-oxide ceramics (TiC and Ti4Al2C2) were detected in as-synthesized and annealed materials by X-ray diffraction experiments. Also, lamella structures of Ti4Al2C2 phase were observed by SEM. It was known that the coefficient of thermal expansion increased with increasing temperature, and decreased with increasing TiC content.

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