Effect of phosphorus segregation on impact toughness variation in 17-4 precipitation hardened stainless steel

Misra, R.D.K.; Prasad, Ch. Rajendra; Balasubramanian, T.V.; Rao, P. Rama

doi:10.1016/0036-9748(86)90497-7

Cited by 32 publications

(13 citation statements)

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“…17). 11 The AES investigations 11 conducted at different temperatures indicated the presence of phosphorus at the grain boundaries; the intergranular concentration of phosphorus exhibited a behavior opposite to that of the impact toughness. The grain boundary concentration of phosphorus was slightly on the lower side for the low-carbon (¾0.02%) melt in comparison to the melt with a relatively higher carbon content (0.035%), which yielded maximum segregation of phosphorus at the grain boundary.…”

Section: Relevance Of Intergranular Segregation Processes In the Undementioning

confidence: 98%

“…The experimentally calculated values are in the range 38-49 kJ mol 1 . Regime II, which is characterized by grain boundary displacement of phosphorus by carbon (site-competitive process), 11 Eqn. (1), can be written as are the free energies of segregation of the solute to the boundary and the free surface, respectively, evaluated at the temperature of fracture (taken as 300 K).…”

Section: Thermodynamic Analysis Of Grain Boundary Cohesionmentioning

confidence: 99%

“…The exact role of the interactions between alloying elements and impurity elements is still far from understood. Interaction processes of the type Nb-C and Nb-P have been invoked to explain striking variations in impact toughness as a function of carbon content of precipitation-hardened stainless steels 11,12 and cold work embrittlement in rephosphorized interstitial-free steels. 13 The technique of AES has been used systematically to arrive at grain boundary segregation isotherms through fracture experiments in a scanning Auger microprobe.…”

Section: Introductionmentioning

confidence: 99%

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Grain boundary segregation and fracture resistance of engineering steels

Misra

2001

Surface & Interface Analysis

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The developments in surface analytical techniques and experimental measurements have made it possible to understand grain boundary segregation processes and related fracture mechanisms. This article shows how experimental contributions have led to the concept of grain boundary segregation isotherms for a complete understanding of grain boundary segregation behavior, and its effect on material properties in terms of the kinetics of segregation, the interaction processes amongst trace and solute elements and the influence of solute elements, heat treatment practice and applied tensile stress on grain boundary segregation processes. The determining role of grain boundary chemistry in obtaining a marked improvement in toughness of engineering steels at the specified levels of strength is elucidated here.

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Section: Relevance Of Intergranular Segregation Processes In the Undementioning

confidence: 98%

Section: Thermodynamic Analysis Of Grain Boundary Cohesionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Grain boundary segregation and fracture resistance of engineering steels

Misra

2001

Surface & Interface Analysis

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“…[191][192][193][194][195][196] It was believed that, with increasing bulk C content, the grain boundary concentration of P 35 a low and b high magnification scanning electron micrographs of the intergranular facets of dynamically embrittled Fe-V alloy. The periodic striations extend across a few grain faces.…”

Section: Stress-induced Segregation and Intergranular Decohesionmentioning

confidence: 99%

Unified mechanism of intergranular embrittlement based on non-equilibrium grain boundary segregation

Liu

Wang

et al. 2013

International Materials Reviews

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The review is aimed at presenting a unified approach in understanding the mechanism of nonequilibrium grain boundary segregation, which can satisfactorily describe the three types of intergranular embrittlement, namely, reverse temper embrittlement of steels, intergranular corrosion embrittlement of stainless steels and intermediate temperature embrittlement of metals and alloys. The review starts with a broad perspective of non-equilibrium grain boundary segregation, including thermally induced non-equilibrium grain boundary segregation and stress induced non-equilibrium grain-boundary segregation. Next, it focuses on the recent progress made in the non-equilibrium grain boundary segregation, including (1) critical time, (2) segregation peak temperature, (3) segregation peak temperature movement for thermally induced and stress induced non-equilibrium grain boundary segregation, and (4) the effect of temperature difference on thermally-induced non-equilibrium grain boundary segregation. Next, the attention is focused on the grain boundary coverage of elements and intergranular embrittlement phenomena. Three types of intergranular embrittlement is analysed in terms of (1) the ductility healing effect induced by the critical time, (2) embrittlement peak or ductility trough induced by the segregation peak temperature, (3) embrittlement peak or ductility trough movement induced by the segregation peak temperature movement and (4) widening and deepening of ductility trough induced by differences in temperature. These experimental phenomena concerning the three types of intergranular embrittlement are consistent with the models of thermally induced and stress induced non-equilibrium grain boundary segregations of impurities, instead of precipitation or equilibrium grain boundary segregation. Towards the end, we visit the subject of grain boundary segregation and associated embrittlement process from the viewpoint of fracture resistance and briefly discuss different perspectives that are of practical significance. List of symbolsA constant b the Burger's vector B Norton coefficient C b (t c ) grain boundary concentration at critical time C b(s50) equilibrium concentration of solute at the grain boundaries C g concentration of solute within the grains C v s~0 ð Þ equilibrium vacancy concentration at grain boundaries C v s~s ð Þ grain boundary vacancy concentration induced by the tensile stress D b the diffusivity D c diffusion coefficients for complexes under or in absence of applied tensile stress D i diffusion coefficients for solute atoms under or in absence of applied tensile stress E the elastic or Young's modulus -E the embrittlement sensitivity in K/at-% of solute at the grain boundary E b formation energy of vacancy solute atom complex International Materials Reviews 2013 VOL 58 NO 5263 E f vacancy formation energy E gb the elastic or Young's modulus of grain boundary region F v the formation energy of a vacancy in the boundary region H Z intergranular Auger peak to peak height of an element normalised with the ...

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“…[1][2][3] A wide range of mechanical properties can be obtained through suitable heat treatments in the temperature range of 723-894 K. [1][2][3][4][5][6] Maximum strength and hardness values are generally obtained after aging at 723 to 783 K, during which coherent copper-rich precipitate clusters are formed. [1][2][3] Aging at higher temperatures (above 813 K) leads to formation of large, incoherent copper-rich precipitates which results in lower strength and hardness and an enhancement of toughness.…”

Section: Introductionmentioning

confidence: 99%

Influence of Frequency on the High-Temperature Fatigue Crack Growth Behavior of 17-4 PH Stainless Steels

Hsu

Lin

2007

Mater. Trans.

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The influence of frequency on fatigue crack growth (FCG) behavior was investigated for three differently heat-treated 17-4 PH stainless steels, namely unaged ''Condition A,'' peak-aged ''Condition H900,'' and overaged ''Condition H1150,'' at 673 and 773 K, and at frequencies ranging from 0.002 to 20 Hz. At 773 K, all heat-treated conditions exhibited similar FCG behavior in which no frequency effect was observed at frequencies higher than 2 Hz and the fatigue crack growth rates (FCGRs) increased with decreasing frequency below 2 Hz. The increase in FCGR at a lower frequency at 773 K was thought to be caused by a time-dependent, oxidation-assisted cracking mechanism. At 673 K, for a given heat-treated condition, the FCGRs increased with decreasing frequency at higher frequencies and leveled off at lower frequencies. Such an anomalous FCG behavior was attributable to a dynamic strain aging (DSA) effect. At a given frequency, when the temperature was increased from 673 to 773 K, the FCGR increased in Condition H1150, but decreased in Conditions A and H900 due to an in-situ overaging and precipitate-coarsening effect during the FCG test for the latter.

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Effect of phosphorus segregation on impact toughness variation in 17-4 precipitation hardened stainless steel

Cited by 32 publications

References 3 publications

Grain boundary segregation and fracture resistance of engineering steels

Grain boundary segregation and fracture resistance of engineering steels

Unified mechanism of intergranular embrittlement based on non-equilibrium grain boundary segregation

Influence of Frequency on the High-Temperature Fatigue Crack Growth Behavior of 17-4 PH Stainless Steels

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