Basic models for solid solution and precipitation hardening during creep are presented for the austenitic stainless steels 25Cr20NiNbN (TP310HNbN, HR3C, DMV310N). The solid solution hardening is a result of the formation of Cottrell clouds of solutes around the dislocations. In addition to slowing down the creep, the solutes increase the activation energy for creep. The increase in activation energy corresponds to the maximum binding energy between the solutes and the dislocations. The formation of fine niobium nitrides during service enhances the creep strength. It is found that the nitrides have an exponential size distribution. In the modelling the critical event is the time it takes for a dislocation to climb over a particle. The creep models can accurately describe the observed time and temperature of the creep rupture strength.
A set of composite materials were developed by blending polymethyl methacrylate (PMMA) with different amounts of micro-fine amorphous silica and titanium dioxide for application as artificial teeth. Wear resistances of these composites were measured with the help of a modified pin-on-disc tribometer and compared with commercial artificial teeth sample in the presence of artificial saliva. It has been observed that under the similar biological condition the powder fillers improved the wear resistances of the artificial teeth as compared to the commercial one under identical condition.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.