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Binary TiMn2 alloys with various compositions were arc melted in an Ar atmosphere. These alloys consist of TiMn2 and a small amount of TiMn depending on all oy composition. Annealed Ti-59.4%Mn exhibits the greatest capacity for hydr ogen absorption and the smallest degradation of capacity during repeated hydrogen absorption and desorption. No apparent macro- and microstructural changes are observed in Ti-59.4%Mn by repeated hydrogenation of 30 cycles. At Mn content higher than 59.4%Mn, the formation of nano-sized Ti-hydride and the lattice expansion due to retained interstitial hydrogen were confirmed in repeatedl y hydrogenated alloys. Pulverized powders were refined in all the alloys with in creasing the number of repeated hydrogenation cycles. Many onion-like cracks are introduced in annealed pure Ta with 100μm equ i-axed grains by holding at 1473K followed by furnace cooling to room te mperature in a hydrogen atmosphere, but no crack is observed after holding at 1473K in a hydrogen atmosphere followed by furnace cooling in an Ar atmosp here. It is concluded that the surface activation is attained in a hydrogen atmo sphere at 1473K and multiple cracking occurs by absorbing a large amount of hydrogen at lower temperature. Volume expansion and dislocations generated by hydrogenation and hydride formation are responsible for multiple cracking. Hyd rogen-induced multiple cracking in Taoccurs in the following sequence: hydroge n absorption, lattice expansion, hydride formation, and crack nucleation and pr opagation. Powder fabrication of Ta by hydrogenation is discussed in comparison with the hydrogen pulverization of intermetallic alloys.