Mamoru Nagao

High-strain-rate superplasticity in ultrahigh-carbon steel containing 10 wt.% Al (UHCS-10Al)

The present study represents a new processing route by which high-strain-rate superplasticity can be obtained in a two-phase, Fe-base alloy. For this study, an ultrahigh-carbon steel containing 10 wt.% Al (UHCS-10Al) was processed by a powder-metallurgy technique. Mechanical attrition was used to introduce a large degree of cold work into pre-alloyed powders, creating the very fine microstructural features necessary for high-strain-rate superplasticity. Because this material contains two phases, {alpha}-Fe and {kappa}-carbide (Fe{sub 3}AlC{sub x} where x = 0.5 to 1), in the range of processing temperatures, a fine grain size was produced upon consolidation and retained during deformation. It is this fine grain size which is responsible for the high-strain-rate superplastic behavior observed.

Studies on Influence of Tantalum Addition in TP310HCbN

SA-213/SA-213M TP310HCbN (UNS S31042) has excellent creep properties. The superior creep strength of this alloy is achieved by precipitation of fine niobium based Z-phase. It is well established that niobium and tantalum have similar physical and chemical properties. We evaluated mechanical properties of tantalum added TP310HCbN, to investigate whether tantalum could be substitute for niobium. It is concluded that niobium can be replaced by tantalum in TP310HCbN.Copyright