Stress corrosion cracking alloy influences

It is not surprising that hardness is important because the mechanical toughness can be expected to decrease with increasing hardness, and the level of residual stress present will also depend on the hardness of the steel, especially for welded components. Thus, the important role of the microstructure in influencing susceptibility to stress-corrosion cracking is consistent with the observation that hardness levels are a good guide to stress-corrosion resistance, but they should not be used universally without due consideration of the specific alloy and the environment in which it is to be used. 

In more recent work embrittlement in water vapour-saturated air and in various aqueous solutions has been systematically examined together with the influence of strain rate, alloy composition and loading mode, all in conjunction with various metallographic techniques. The general conclusion is that stress-corrosion crack propagation in aluminium alloys under open circuit conditions is mainly caused by hydrogen embrittlement, but that there is a component of the fracture process that is caused by dissolution. The relative importance of these two processes may well vary between alloys of different composition or even between specimens of an alloy that have been heat treated differently. 

In metal alloys the combination of stress and environment can also lead to premature failures, indicated as Stress Corrosion Cracking, SCC [1]. The influence of the environment on SCC is generally of a chemical nature a chemical reaction occurs between the metal and the environment. Most of the research published on the ESC of polymers focuses on ESC in which the environment influences the material only physically [2-8]. In such cases the mechanism of ESC is studied and models are established for ESC prediction [9]. These models for physical ESC are based predominantly on the solubility parameters of the considered polymer/environment combination. In other words, ESC is mainly a consequence of polymer softening, i.e. it is a reduction of the interaction between the polymer chains that lowers the yield stress. 

E.N. Pugh, J.V. Craig, and W. Montaguer, Factors Influencing the Path of Stress-Corrosion Cracking in Alpha-Phase Copper Alloys Exposed to Aqueous Ammonia Environments, Trans. ASM, Vol 61, 1968, p 468-473... 

Under the influence of static mechanical tensile stress, various types of stress corrosion cracking can arise while alternating mechanical stress leads to corrosion fatigue, which occurs in both fully active and passive alloy systems. 

Bucci, R. J., "Environment Enhanced Fatigue and Stress Corrosion Cracking of a Titanium Alloy Plus a Simple Model for the Assessment of Environmental Influence on Fatigue Behavior, Ph.D. dissertation, Lehigh University, Bethlehem, PA, 1970. 

Treseder, R. S., Influence of Yield Strength on Anodic Stress Corrosion Cracking Resistance of Weldable Carbon and Low Alloy Steels with Yield Strengths Below 100 ksi, WRC Bulletin, Vol. 243, November 1978, pp. 27-33. 

Ebtehaj, K., Hardie, D., and Parkins, R. N., "The Influence of Chloride-Chromate Solution Composition on the Stress-Corrosion Cracking of Mg-Al Alloy, Corrosion Science, Vol. 9, 1988, pp. 849-851. 

Crooker T. W. and Hauser, J. A., II, A Literature Review on the Influence of Smaii-Amplitude Cyclic Loading on Stress Corrosion Crack Growth in Alloys, NRL Memorandum Report 5763, Naval Research Laboratory, Washington DC, April 3 (1988)... 

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