جستجوی مقالات مرتبط با کلیدواژه « recrystallization kinetics » در نشریات گروه « مواد و متالورژی »

Austenitic stainless steels are widely used in different industries because of their attractive mechanical properties as well as their reasonable corrosion resistance. While different works have been focused on the severe plastic deformation of austenitic stainless steels, recrystallization kinetics of these alloys after the imposition of severe plastic deformation is remained less studied. The aim of this work is to study the recrystallization kinetic of austenitic stainless steels 316L after the imposition of severe plastic deformation using equal channel angular pressing. For this purpose, the alloy is processed by 0, 1, 2, and 4 passes of the mentioned process at 310 ºC by route BC. Afterwards the processed specimens are subjected to annealing at 800 ºC for a duration of 9 to 30 min. During these procedure, the kinetic of recrystallization is studied using the optical microscopy while the optical microscopy results are analyzed by the MIP5 image analyzing software. Also, the volume fraction of recrystallization is interpreted using the JMAK model. Results show that the exponent of recrystallization duration in the JMAK model is between 3 and 4. The mechanism probably involving these phenomena are discussed.

In the current study, the recrystallization behavior of 75% cold-rolled Fe-22Mn-10Al-1.4C steel during annealing at 750, 770, 790, 810, and 830°C was studied. X-ray diffraction patterns and optical microscopy were used to characterize microstructures. The Vickers Micro-hardness test was used to characterize recrystallization kinetics during annealing. Johnson-Mehl-Avrami-Kolmogorov (JMAK) model was used to evaluate the experimental data. The as-homogenized microstructure illustrated only austenite with a high fraction of annealing twins, and austenite to martensite phase transformation was not observed after quenching at a high temperature and also until high thickness reduction. Avrami exponent was decreased from 0.76 to 0.42, with increasing the annealing temperature from 750 to 830°C. The activation energy value was determined to be ~175 kJ/mol, which was slightly higher than the diffusion activation energy of carbon in austenite.

In this work dynamic recrystallization behavior of AISI 403 martensitic stainless steel was studied using hot compression tests over temperature range of 900 C -1200 C and strain rate range of 0.001 s-1 - 1 s-1. The obtained flow curves showed that the hot compression behavior of the alloy is controlled by dynamic recrystallization. The flow stress and strain corresponding to the critical, peak and onset of steady state region were related to the Zener-Hollomon parameter using simple power equations. The variation of dynamic recrystallization fraction with strain showed that restoration kinetics is enhanced with increasing temperature and decreasing strain rate. The development of DRX was modeled using Avrami Kinetics equation. The equations proposed by Baragar and Cingara-McQueen were used to develop a new model capable of predicting the flow curves up to the onset of steady state flow region. This work softening is mainly controlled by the phenomenon dynamic recrystallization.