Coupled effects of banded structure and carbide precipitation on mechanical performance of Cr–Ni–Mo–V steel

AbstractThe vulnerability of tempered martensitic steel to hydrogen embrittlement (HE) has attracted attention from a number of researchers. Although utilizing carbide precipitation is one of effective methods to improve HE resistance, few studies have focused on the effects of carbide characteristics, such as the chemical composition and morphology of carbide. This work clarifies the role of Mo carbide and V carbide in the HE behavior of tempered martensitic steels with four steels whose chemical composition was carefully controlled. The beneficial effect of carbides is discussed in terms of hydrogen trapping and fracture mode. The low amount of trapped hydrogen and undissolved carbide led to excellent HE resistance of Mo carbides compared to V carbides. In addition, the superior mechanical performance of Cr-Mo steel was also interpreted by the effect of Cr addition as well as Mo carbides.

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Strain-induced martensite effects on transgranular carbide precipitation in type 304 stainless steels

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100087331 ◽

1991 ◽

Vol 49 ◽

pp. 604-605

Author(s):

A.H. Advani ◽

L.E. Murr ◽

D. Matlock

Keyword(s):

Heat Treatment ◽

Grain Boundary ◽

Stress Corrosion Cracking ◽

Stainless Steels ◽

Deformation Twin ◽

Austenitic Stainless Steels ◽

Carbide Precipitation ◽

Strain Induced Martensite ◽

Type 304

Thermomechanically induced strain is a key variable producing accelerated carbide precipitation, sensitization and stress corrosion cracking in austenitic stainless steels (SS). Recent work has indicated that higher levels of strain (above 20%) also produce transgranular (TG) carbide precipitation and corrosion simultaneous with the grain boundary phenomenon in 316 SS. Transgranular precipitates were noted to form primarily on deformation twin-fault planes and their intersections in 316 SS.Briant has indicated that TG precipitation in 316 SS is significantly different from 304 SS due to the formation of strain-induced martensite on 304 SS, though an understanding of the role of martensite on the process has not been developed. This study is concerned with evaluating the effects of strain and strain-induced martensite on TG carbide precipitation in 304 SS. The study was performed on samples of a 0.051%C-304 SS deformed to 33% followed by heat treatment at 670°C for 1 h.

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Carbide precipitation and chromium depletion on coherent twin boundaries in deformed 304 stainless steels

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130717 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1216-1217

Author(s):

A.H. Advani ◽

L.E. Murr ◽

D.J. Matlock ◽

W.W. Fisher ◽

P.M. Tarin ◽

...

Keyword(s):

Grain Boundaries ◽

Stainless Steels ◽

Interfacial Free Energy ◽

Carbide Precipitation ◽

Twin Boundaries ◽

Invariant Structure ◽

Heat Treated ◽

Constant Structure ◽

Cr Depletion

Coherent annealing-twin boundaries are constant structure and energy interfaces with an average interfacial free energy of ∼19mJ/m2 versus ∼210 and ∼835mJ/m2 for incoherent twins and “regular” grain boundaries respectively in 304 stainless steels (SS). Due to their low energy, coherent twins form carbides about a factor of 100 slower than grain boundaries, and limited work has also shown differences in Cr-depletion (sensitization) between twin versus grain boundaries. Plastic deformation, may, however, alter the kinetics and thermodynamics of twin-sensitization which is not well understood. The objective of this work was to understand the mechanisms of carbide precipitation and Cr-depletion on coherent twin boundaries in deformed SS. The research is directed toward using this invariant structure and energy interface to understand and model the role of interfacial characteristics on deformation-induced sensitization in SS. Carbides and Cr-depletion were examined on a 20%-strain, 0.051%C-304SS, heat treated to 625°C-4.5h, as described elsewhere.

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Deformation effects on transgranular carbide precipitation in 304 stainless steels

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100121703 ◽

1992 ◽

Vol 50 (1) ◽

pp. 260-261

Author(s):

A.H. Advani ◽

L.E. Murr ◽

D.J. Matlock ◽

W.W. Fisher ◽

P.M. Tarin ◽

...

Keyword(s):

Stainless Steels ◽

True Strain ◽

Carbide Precipitation ◽

Material Research ◽

Chromium Depletion ◽

Engineering Strain ◽

Twin Fault ◽

Heat Treated ◽

Strain Induced Martensite ◽

The Relationship

Plastic deformation is a key variable producing accelerated intergranular (IG) carbide precipitation and chromium-depletion (sensitization) development in stainless steels. Deformation above 20% also produces transgranular (TG) carbides and depletion in the material. Research on TG carbides in SS is, however, limited and has indicated that the precipitation is site-specific preferring twin-fault intersections in 316 SS versus deformation-induced martensite and martensite lath-boundaries in 304 SS. Evidences indicating the relation between martensite and carbides were, however, sketchy.The objective of this work was to fundamentally understand the relationship between TG carbides and strain-induced martensite in 304 SS. Since strain-induced martensite forms at twin-fault intersections in 304 SS and the crystallography of the transformation is well understood, we believed that it could be key in understanding mechanisms of carbides and sensitization in SS. A 0.051% C, 304 SS deformed to ∽33% engineering strain (40% true strain) and heat treated at 670°C/ 0.1-10h was used for the research. The study was carried out on a Hitachi H-8000 STEM at 200 kV.

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271 Cardiac re-synchronization may have a beneficial effect on right ventricular mechanical performance

EP Europace ◽

10.1016/s1099-5129(05)80191-6 ◽

2005 ◽

Vol 7 ◽

pp. 65-65

Keyword(s):

Beneficial Effect ◽

Right Ventricular ◽

Mechanical Performance

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The Mechanical Performance of Carbon Fibres- Addressing the Role of Microstructure

10.33599/nasampe/s.19.1459 ◽

2019 ◽

Author(s):

Peter Peter ◽

Claudia Creighton ◽

David Fox ◽

Pablo Mota Santiago ◽

Adrian Hawley ◽

...

Keyword(s):

Mechanical Performance ◽

Carbon Fibres

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Microstructural and Mechanical Behaviour Evaluation of Mg-Al-Zn Alloy Friction Stir Welded Joint

International Journal of Automotive and Mechanical Engineering ◽

10.15282/ijame.17.3.2020.08.0612 ◽

2020 ◽

Vol 17 (3) ◽

pp. 8150-8159

Author(s):

Kulwant Singh ◽

Gurbhinder Singh ◽

Harmeet Singh

Keyword(s):

Heat Treatment ◽

Friction Stir Welding ◽

Magnesium Alloys ◽

Mechanical Performance ◽

Fuel Efficiency ◽

Research Work ◽

Grain Structure ◽

Tensile Fracture ◽

Friction Stir ◽

The Impact

The weight reduction concept is most effective to reduce the emissions of greenhouse gases from vehicles, which also improves fuel efficiency. Amongst lightweight materials, magnesium alloys are attractive to the automotive sector as a structural material. Welding feasibility of magnesium alloys acts as an influential role in its usage for lightweight prospects. Friction stir welding (FSW) is an appropriate technique as compared to other welding techniques to join magnesium alloys. Field of friction stir welding is emerging in the current scenario. The friction stir welding technique has been selected to weld AZ91 magnesium alloys in the current research work. The microstructure and mechanical characteristics of the produced FSW butt joints have been investigated. Further, the influence of post welding heat treatment (at 260 °C for 1 h) on these properties has also been examined. Post welding heat treatment (PWHT) resulted in the improvement of the grain structure of weld zones which affected the mechanical performance of the joints. After heat treatment, the tensile strength and elongation of the joint increased by 12.6 % and 31.9 % respectively. It is proven that after PWHT, the microhardness of the stir zone reduced and a comparatively smoothened microhardness profile of the FSW joint obtained. No considerable variation in the location of the tensile fracture was witnessed after PWHT. The results show that the impact toughness of the weld joints further decreases after post welding heat treatment.

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