Embrittling effect

Its influence appears to result primarily from suppression of the embrittling effects of moisture in air (75). The role of chromium, on the other hand, is to reduce the embrittling effects of oxygen at temperatures above about 500°C (76). 

An embrittling effect, the mechanism of which is stiU debated, is possible with a hydrogen content of more than ca 3 ppm. The content of hydrogen and other gases can, however, be reduced by vacuum dagassing. 

The low temperature impact strength of stmctural steels was found to be significantly improved with the additions of 0.022—0.008% Te. The low (—40° C) temperature impact strength of a steel annealed at blue brittie temperature of 350°C did not show any embrittlement effect with the addition of. 002% Te (76). 

The mechanical properties of these metals are markedly affected by traces of impurities such as O, N and C which have an embrittling effect on the metals, making them difficult to fabricate. 

Silicon may be present in high-chromium irons in amounts varying between 0-5 and 2-5%. Its effect is to increase fluidity in the foundry and improve the surface quality of castings. Further effects are to refine the eutectic carbides in the iron, to produce a more uniform structure and to raise the temperature at which the matrix transforms from ferrite to austenite with consequent dimensional changes. Additions above 2-5% have an embrittling effect. 

Heat-resisting steels have limited uses in contact with molten metals. They are not recommended for use with molten zinc, cadmium, aluminium, antimony or copper, because of excessive attack and embrittlement effects. In brazing and silver soldering, contact between the molten non-ferrous alloy and the steel occurs for only a very limited period of time. 

The embrittlement effect can be largely removed by ageing the steel at about 150 C, but even then the original ductility is not entirely restored. 

Integrity management processes should take into account the embrittlement effects of dry hydrogen gas on carbon steel pipeline materials and welds used to join pipe sections. 

The metals are comparatively soft and ductile impurities generally have hardening and embrittling effects. Notice, as a result of the lanthanide contraction, the nearly equal atomic volumes of Nb and Ta, and the consequent very different values of the densities. 

The SUDICRETE additive modifies the whole concrete system, not just the sulfur binder, so the effect of the SUDICRETE additive is permanent and does not show the embrittling effects observed in other modifier technologies. 

The EAM and MEAM potentials once determined from electronics principles calculations [178] have been used to reproduce physical properties of many metals, defects, and impurities. For example, EAM molecular statics, molecular dynamics, and Monte Carlo simulations were performed on hydrogen embrittlement effects on dislocation motion and plasticity [46,179-181]. These potentials have been used to analyze plasticity [74,144,145,148-150,182,183], cracks and fracture [117,184], and fatigue [119, 120, 185, 186]. 

Enhanced dissolution by mechanisms such as the above introduce vacancies and divacancies on the surface which diffusebackinto the metal to grain boundaries, where they cause enhanced creep and plastic deformation. This pressure of these would eventually lead to failure (Uhlig and Revie, 1985). An H embrittlement effect may add to this mechanism (Thomas and Wei, 1992). 

Compensate the embrittlement-effect of the large surface area of inclusions... 

Surface films appear to play a major role in the initiation of SCC and may also contribute to hydrogen embrittlement effects. It is assumed that the main role of the surface film is to localize the damage inflicted on the material by the environment. This can be caused by mechanical breakdown of the protective film by slip step or electromechanical breakdown of the passive film.95 SCC may be related to the nature of the surface film. It has been observed that the SCC of C-Steels is related to the presence of magnetite in several low -temperature environments (around 90°C), except... 

Bloating/Crushing. The process is based upon the embrittling effect when heating cemented carbides to about 1800 °C followed by rapid quenching. Embrittlement is the consequence of WC grain growth, formation of brittle phases, and thermally induced stresses. 

Hafnium is a lustrous, silvery, ductile metal with a high melting point. The mechanical properties of the metal are markedly affected by traces of impurities such as O, N, and C which have an embrittling effect on the metal, making it difficult to fabricate. The alloy tantalum hafnium carbide (Ta4HfCs), with a melting point of 4215 °C, is one of the most refractory substances known. 

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