Performance criteria, resist

E. A. Lange and F. J. Loss, Dynamic Tear Energy—A Practical Performance Criterion for Fracture Resistance, NRL Report 6975, Naval Research Laboratories, Washington, D.C. (1969). 

An efficient breeding programme for drought resistance is difficult to achieve by using the sole criterion of yield performance under stress, so... 

Toughness can influence the performance of materials under conditions of erosion-corrosion. The soft metals are often more susceptible to erosion corrosion because they are more susceptible to mechanical wear. The toughness is a good criterion for the resistance to the mechanical erosion or abrasion, but this is not necessarily a good criterion to predict the resistance to the erosion-corrosion. Stellite (Co-Cr-W-Fe-C alloy), which has better toughness than 18-8 stainless steel, showed better resistance to cavitation erosion on a water brake.25... 

The data in Table IV show that CP-formulated samples have excellent intrinsic attrition resistance. The AI of 3.5 for CP-2(4) exceeds the performance of all six commercial samples tested even 10.7 for CP-25 is within the range of AI values obtained for the commercial materials. With rehydratable alumina in the matrix, microspheres with superior attrition resistance can be manufactured. Thus, the second criterion for success was met. 

As with all standardized tests (e g., the ASTM A 262 procedures previously discussed), correlations must be established between the EPR Pa values and service performance. For example, a criterion of Pa < 2 C/cm2 has been proposed for adequate resistance to intergranular corrosion leading to intergranular stress-corrosion cracking (IGSCC) of type 304 and 304L pipe and welds. Other limits would be set depending on the material, application, and environment (Ref 105, 106). 

A balanced combination of properties is the criterion of performance. In tread-wear resistance, cold butadienerstyrene tires are approximately 20-30 per cent superior to natural-rubber or hot rubber treads. However, in tire carcass or sidewalls, natural rubber exhibits superior performance, especially in truck tires, because of lowfeV heat build-up. 

We must take note of the behavior of the remaining materials in terms of chemical resistance. Consider the example of a salty aqueous fluid. The database includes a quahtative appreciation criterion, which means that we cannot cany out a classification or elimination on the basis of the limit values. We propose to visualize the hierarchical classification of the remaining materials in relation to this criterion in order to determine the maximum or minimum acceptable performance on the basis of that of a reference material (Figure 8.4). 

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