In recent years, in fields of an eco-friendly automobile, an advanced industrial machine, and a precision electronic device, controlling of vibration damping behavior of the sintered materials is required. In this paper, vibration damping analysis of Cu-Sn/Carbon fiber sintered composite materials was performed by frequency response function of FFT analyzer, and the results was compared with Cu-Sn/Graphite sintered composite materials. Cu, Sn elemental powders and Carbon fiber were used as initial substances. The powders and the fiber were mixed and pressed into a plate shaped compact with 200 MPa. Using a vacuum furnace, the green compact was sintered at 825-1075°C for 1 hour. By changing the mixing ratio and the sintering temperature, some kinds of the composite material plates were prepared. For the composite material obtained, microstructure, Vickers hardness, compression strength and vibration behavior were investigated. The composite materials were consisted from the crystal grain of 17-70 μm, and the mixed Carbon fiber were dispersed in the microstructure. Twin crystal was also found in the composite materials obtained. Vibration damping behavior of the Cu-Sn/Carbon fiber sintered composite material was affected by solubility element, grain boundary, dispersed Carbon fiber, and twin crystal in composite material. KEY WORDS vibration damping coefficient, FFT analyzer, lumped mass model, frequency response function, Cu-Sn/Carbon fiber sintered composite material

In this paper, the effects of the third element (Cr, Mo, and Mn) on the mechanical properties of TiAl intermetallic compound made by combustion synthesis were considered. The powders of Ti, Al, Co, and the third element (Cr, Mo, and Mn) were mixed. The green compact was made from the mixed powder, and was reacted in an electric vacuum furnace. The density, the microstructure, the hardness, and the compressive strength of the obtained synthesized products were investigated. The density of the synthesized products became more than 90 by Co/Al sintering additive. The grain size of them was 20 mm. The components of the synthesized products were TiAl and Ti 3 Al. As addition quantity of the third element increased, the hardness of them rose and the strength of them fell. The ductility of the synthesized product that added Cr 5 especially is excellent. Further the fracture surfaces of them were discussed.

The surface reforming of Ti wire by powder metallurgy was investigated in this study. Pure Ni powder, Ni/Ti powder and Ni/ Al powder were used as coating materials. A piece of Ti wire （φ＝1.0 mm） was placed in an alumina crucible, and coating materials （Ni powder, Ni/Ti premixed powder, Ni/Al premixed powder） were filled around the Ti wire. The alumina crucible was vacuum sealed in a quartz tube with 2 ×10 -3 Pa. The quartz tube was heated in an electric furnace for 60 min. For the test piece obtained, microstructure, phase and Vickers hardness were measured. A uniform compound layer was formed when the Ni / Al premixed powder was used as the coating material. The intermetallic compound layer was consisted of （Ti 3 Al＋NiTi） , （Ti 3 Al＋Ti 2 Ni＋τ 4 ） phases. The surface reforming of Ti wire was able to be performed by dipping heat of Ti wire into Ni/Al premixed powder. ［doi:10.2320/jinstmet.J2018005］

From analyzing the cylindrical model and the flat plate reaction model, it is guessed the differences were caused by the contact area of Cu/Cu 3 Al/Al interface and Al concentration of Cu 3 Al phase formed in Cu wires and Cu plates.

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