2材料科学基础英文版课件 (4).ppt

2材料科学基础英文版课件_(4).ppt2018/6/25
Equilibrium and Stress-induced Non-Equilibrium Grain Boundary Segregations of Phosphorus in a Steel
Song Shenhua

2018/6/25
Preface (1)
Grain boundary segregation (GS)
Effects of grain boundary segregation on the properties of materials

Mechanical, corrosion, electrical, and ic properties
., in structural materials, such as steel and Ni alloys
Segregation of detrimental elements such as S, P, Sn, and Sb – decreasing the grain boundary cohesion – grain boundary weakening
Segregation of beneficial elements such as B, C and Be – increasing the grain boundary cohesion – grain boundary strenthening
Preface (2)
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Preface (3)
GS
EGS
NEGS
NEGS induced by high temperature deformation
Stress induced NEGS
Irradiation induced NEGS
Thermally induced NEGS
……
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Preface (4)
steel
Applied stress
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Outline (1)
Equilibrium grain boundary segregation
Segregation of phosphorus and molybdenum
Introduction, experiment, results and discussion, summary
Relationship between phosphorus boundary concentration and ductile-to-brittle transition temperature (DBTT)
Introduction, experiment, results and discussion, summary
Effect of phosphorus grain boundary segregation on intergranular fracture
Introduction, experiment, results and discussion, summary
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Outline (2)
Stress-induced non-equilibrium grain boundary segregation
Introduction, experiment, results and discussion, summary
Conclusions
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Equilibrium grain boundary segregation (1)
(McLean, 1957)
(Seah, 1977)
(Guttmann, 1975)
Segregation thermodynamics
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Equilibrium grain boundary segregation (2)
Segregation ics
(McLean, 1957)
erfc(x) = 1 – erf(x)