Non-equilibrium grain-boundary segregation in austenitic alloys

Faulkner, R. G.

doi:10.1007/bf00738626

Cited by 215 publications

(98 citation statements)

References 11 publications

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“…A large number of supersaturated vacancies can be produced in a material during quenching, irradiation, or deformation, and thus, NGS of B can be observed through these kinds of processes. In quenching-induced segregation, [11][12][13] supersaturated vacancies formed during quenching from a higher temperature to a lower temperature are annihilated at grain boundaries during isothermal holding; then vacancy-boron complexes diffuse from the grain interior to the grain boundaries along the vacancy gradients with an increasing holding time (HT) at a holding temperature T H , and the maximum grain boundary segregation of B occurs at a certain time that is generally known as the critical time. [12] NGS caused by diffusion of vacancy-boron complexes gradually disappears if sufficient time is allowed for the system to reach full equilibrium.…”

Section: The Addition Of a Small Amount Of Boron (B)mentioning

confidence: 99%

Cooling Rate Dependence of Boron Distribution in Low Carbon Steel

Mun

Shin

Cho

et al. 2011

Metall Mater Trans A

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The behavior of boron (B) segregation to austenite grain boundaries in low carbon steel was studied using particle tracking autoradiography (PTA) and secondary ion mass spectroscopy (SIMS). An effective time method was used to compare the cooling rate (CR) dependence of this segregation during continuous cooling and its time dependence during isothermal holding. Comparison of these segregation behaviors has confirmed that the CR dependence of B segregation agrees well with its time dependence and is mainly a result of the phenomenon of nonequilibrium segregation. Based on the CR dependence of B segregation, the continuous cooling transformation behavior of B-bearing steel as compared with B-free steel was also investigated using dilatometry and microstructural observations. The addition of a small amount of B to low carbon steel retarded significantly the austenite-to-ferrite transformation and finally expanded the range of cooling programs that result in the formation of bainitic microstructures. Analysis of the B distribution has confirmed that this retardation effect of B on ferrite transformation is attributed to the CR dependence of B segregation to austenite grain boundaries during cooling after austenitization.

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Section: The Addition Of a Small Amount Of Boron (B)mentioning

confidence: 99%

Cooling Rate Dependence of Boron Distribution in Low Carbon Steel

Mun

Shin

Cho

et al. 2011

Metall Mater Trans A

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“…According to the isothermal kinetics of the NGS of boron, the processes of non-equilibrium segregation can be divided into segregation and desegregation processes [8]. When the sample is cooled quickly from a higher temperature to a lower temperature and then held at this lower temperature, vacancy-boron complexes begin to diffuse towards the grain boundaries.…”

Section: Time Dependence Of Boron Distribution In Lowmentioning

confidence: 99%

A Study on the Behavior of Boron Distribution in Low Carbon Steel by Particle Tracking Autoradiography

Mun¹,

Shin²,

Koo³

2011

Nuclear Engineering and Technology

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“…Considerable experimental and theoretical work has been carried out on the non-equilibrium segregation (and desegregation) of solute atoms as induced by vacancy currents in metals and alloys. [14][15][16][17] The non-equilibrium segregation of B to grain boundaries during quenching has been analyzed by Williams et al 15) as well as by Faulkner 16) on the basis of a model originally proposed by Aust and Westbrook.…”

Section: Segregation Behavior Of B and Pmentioning

confidence: 99%

Effect of Cooling Rate after Recrystallization on P and B Segregation along Grain Boundary in IF Steels

2003

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Many researchers revealed that the addition of small amount of boron (B) significantly suppresses the intergranular fracture (IGF) induced by segregated phosphorous (P) along grain boundaries in iron and steels. However the details of this suppression have not been clarified yet. In the present study, the behavior of B and P during heat treatment and the mechanism of toughening caused by B in interstitial free (IF) steels containing P was examined using alpha-particle track etching (ATE), tensile testing, Auger electron spectroscopy (AES) and scanning electron microscopy (SEM). The results of ATE exhibit that the degree of grain boundary segregation of B depends on the cooling rate from 850°C and shows maximum at about 10°C/s for high B-low P steel while it shows maximum at about 555°C/s for high B-high P steel. The results of ATE also reveal that low P steel shows higher B segregation than high P steel at all cooling rates, while the difference is reduced by increasing the cooling rate. It was found that elongation at low temperatures is improved when B segregates along grain boundaries. The results of AES indicate that the grain boundary segregation of B markedly decreases the segregation of P and consequently the elongation is enhanced. Therefore, controlling of the cooling rate after recrystallization decreases the brittleness caused by P in IF steel. Segregation of B and P after heat treatment can be explained by a duplex equilibrium and non-equilibrium mechanism before and during cooling.

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Non-equilibrium grain-boundary segregation in austenitic alloys

Cited by 215 publications

References 11 publications

Cooling Rate Dependence of Boron Distribution in Low Carbon Steel

Cooling Rate Dependence of Boron Distribution in Low Carbon Steel

A Study on the Behavior of Boron Distribution in Low Carbon Steel by Particle Tracking Autoradiography

Effect of Cooling Rate after Recrystallization on P and B Segregation along Grain Boundary in IF Steels

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