سینتیک استحاله های مارتنزیتی در فولادها

Kinetics of martensite transformations in steels

سینتیک استحاله های مارتنزیتی در فولادها

ABSTRACT

Dislocation theory of the mechanism and kinetics of martensitic transformation has provided a foundation for the prediction of constitutive relations for transformation plasiticity. Application to the control of stress-state dependent shaping of stress–strain behavior has demonstrated substantial improvements in uniform ductility and ductile fracture toughness. The advance of such predictive science continues to play a central role in the new enterprise of science-based materials design.

 

جوشکاری حالت جامد آلیاژ برنج Cu-Zn و فولاد

Solid-state bonding of alloy-designed Cu–Zn brass and steel

associated with phase transformation by spark plasma sintering

جوشکاری حالت جامد آلیاژ برنج Cu-Zn مخصوص و فولاد وابسته به استحاله فازی

به وسیله ی زینترینگ به کمک قوس پلاسما

ABSTRACT

Solid-state bonding between steel and a Cu alloy was studied to investigate fabrication of advanced bimetallic composites by using spark plasma sintering (SPS). In order to obtain proper bonding strength between the mating materials, Si and Al were alloyed to Cu–Zn brass to enhance interdiffusion with steel. The alloying elements diffused from the Cu alloy to steel, which transformed from the gamma to alpha phase during bonding. Owing to the phase stability of steel, the new columnar microstructure that evolved during the transformation across the joint interface showed high bonding strength between the mating alloys. The samples bonded without fracture, defects, or inhomogeneous deformation. Microstructural observations, elementary mapping, and mechanical testing demonstrated that the SPS technique and specific bonding parameters enhanced the interdiffusion between the metals. This novel method would be well suited to strengthen bonding between two dissimilar metals with different diffusion coefficients.