A new model has been developed to describe the mechanism which determines the preserving or reversing of the phase transformation for diamond and hard BN (boron nitride) during a shock wave experiment. The model considers the principal distribution of parameters, such as stresses, temperature, mass velocity, and density both within these materials, and in their mixtures with other materials. Four main stages in the shock wave experiment are identified to reflect the qualitative changes in these parameters. The possibility of preserving synthesized hard phases of carbon and BN is shown to depend primarily on the characteristics of the release process after maximum pressures are achieved. If the release process is almost adiabatic, then the transformation of strain energy into heat and powerful tensile stresses causes graphitization. If the release process is almost isentropic, then conditions can be favorable for preservation of the hard phases. 0 I995 American Institute of Physics.
A stationary model of friction joining of aluminum-based MMC (metal matrix composite) material has been developed. This model allows the prediction of the temperature and strain rate distributions in the base material adjacent to the joint interface for different shear stress values and joint interface temperatures. The calculated results are most applicable to situations where the amount of axial shortening during friction joining is limited. Published by Elsevier Science Ltd Resume-Un modele stationnaire d'assemblage par friction de materiau CMM (composite a matrice metallique) a base d'aluminium a ete developpe. Ce modele permet la prediction des distributions de temperature et de vitesse de deformation dans Ie materiau de base adjacent a l'interface assemblee pour differentes valeurs de cisaillement et de temperatures de l'interface assemblee. Les resultats calcules s'appliquent Ie mieux aux situations ou la quantite de retrecissement axiallors de l'assemblage par friction est limitee.
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.