Fabrication of TiC-20 mass%Ni Cermet Using MA-PCS Process

Mechanical alloying and pulsed-current sintering were used to synthesize TiC-20 mass%Ni cermet with ultra-fine TiC particles dispersed. The mixture, in which Ti and Ni elements were uniformly distributed, was prepared by mechanical alloying of Ti, Ni and graphite powders for 18 ks. TiC particles were produced in the mixture milled for longer than 18 ks through a combustion synthesis reaction during heating. Mechanically alloyed Ti-C-Ni composite powder milled for 18 ks was consolidated using pulsed-current sintering at 1223 K under 70 MPa pressure. The sintered compact consisted of TiC and Ni. The average grain size of TiC particles in the sintered body was 0.80 mm. The relative density of the sintered compact reached 92% of the theoretical one; its Vickers hardness was 2260 Hv

Investigation of optimal route to fabricate submicron-sized Sm2Fe17 particles with reduction-diffusion method

Submicron-sized Sm2Fe17 powder samples were fabricated by a non-pulverizing process through reduction-diffusion of precursors prepared by a wet-chemical technique. Three precursors having different morphologies, which were micron-sized porous Sm-Fe oxide-impregnated iron nitrate, acicular goethite impregnated-samarium nitrate, and a conventional Sm-Fe coprecipitate, were prepared and subjected to hydrogen reduction and reduction-diffusion treatment to clarify whether these precursors could be convert to Sm2Fe17 without impurity phases and which precursor is the most attractive for producing submicron-sized Sm2Fe17 powder. As a result, all three precursors were successfully converted to Sm2Fe17 powders without impurity phases, and the synthesis route using iron-oxide particle-impregnated samarium oxide was revealed to have the greatest potential among the three routes

Pulsed Current Sintering of Amorphous Titanium Alloy Powder Synthesized by Mechanical Alloying Process

Ti, Fe and Si powders using a planetary ball milling for 720 ks. The amount of collectable powder milled for 720 ks decreased with increasing Fe content in the MA powder. An amorphous phase was generated for all of the powders milled for 720 ks. The crystallization temperature of Ti– 2 at%Fe–10 at%Si powder synthesized by MA for 720 ks was higher than that of the other MA powders. Ti–2 at%Fe–10 at%Si powder prepared by milling for 720 ks, which contained amorphous phase, was consolidated using a pulsed current sintering apparatus under a high pressure. The compact consolidated at 673K under a pressure of 1500MPa was almost densified with the retention of amorphous phase. The pulsed current sintering under a high pressure is a powerful technique to consolidate amorphous powder into a bulk material