The formation of austenite during intercritical annealing at temperatures between 740 and 900 °C was studied in a series of 1.5 pct manganese steels containing 0.06 to 0.20 pct carbon and with a ferrite-pearlite starting microstructure, typical of most dual-phase steels.

Formation of Austenite During Intercritical Annealing of Dual-Phase Steels

Nucleation in solids: The induction and steady state effects

Nucleation theory and the solubility product of niobium, carbon, and nitrogen in austenite have been used to derive equations for the start of Nb (C, N) precipitation as a function of temperature and composition. The predicted curves have been compared with the experimental observations of several authors to determine the effects of thermomechanical processing variables on the density of preferred nucleation sites and to incorporate these in the equations. Good agreement between the predicted and observed forms of precipitation curve is obtained with consistent constants in the equations when account is taken of the influence of different methods of detecting the onset of precipitation. Combining the calculated precipitation start curves with the dependence of recrystallization kinetics on composition and thermomechanical process variables when all niobium is in solution leads to prediction of the lower temperature limit for complete recrystallization and of the upper temperature limit for effecti...

Effect of composition and process variables on Nb(C, N) precipitation in niobium microalloyed austenite

Modelling the kinetics of strain induced precipitation in Nb-microalloyed steels

Friction stir welding (FSW), a highly efficient solid-state joining technique, has been termed as “green” technology due to its energy efficiency and environment friendliness. It is an enabling technology for joining metallic materials, in particular lightweight high-strength aluminum and magnesium alloys which were classified as unweldable by traditional fusion welding. It is thus considered to be the most significant development in the area of material joining over the past two decades. Friction stir processing (FSP) was later developed based on the basic principles of FSW. FSP has been proven to be an effective and versatile metal-working technique for modifying and fabricating metallic materials. FSW/FSP of aluminum alloys has prompted considerable scientific and technological interest since it has a potential for revolutionizing the manufacturing process in the aerospace, defense, marine, automotive, and railway industries. To promote widespread applications of FSW/FSP technology and ensure t...

Recent Advances in Friction Stir Welding/Processing of Aluminum Alloys: Microstructural Evolution and Mechanical Properties

Growth of grain boundary precipitates in Al-4% Cu by interfacial diffusion

Comparison of relative interfacial energies of disordered interphase (α:θ) and grain (α:α) boundaries at grain boundary precipitates in Al-4% Cu during growth and at equilibrium

H.B. Aaron

Papers

Growth of grain boundary precipitates in Al-4% Cu by interfacial diffusion

Comparison of relative interfacial energies of disordered interphase (α:θ) and grain (α:α) boundaries at grain boundary precipitates in Al-4% Cu during growth and at equilibrium

Preferential diffusion along interphase boundaries

Zener disaccommodation in dilute F.C.C. Co-Ti alloys