Читать книгу Root Cause Failure Analysis - Trinath Sahoo - Страница 130

For each type of expected failure mechanism, a combination of the mechanical, physical, and chemical properties should be possessed by the material to be selected for developing a design. For example, if failure of a component is expected to occur by excessive plastic deformation at room temperature and high temperature conditions, then yield strength and creep respectively will be important criterion for design. Similarly, if failure of a component is expected to occur by fracture under overloads, fluctuating loads, and impact loads then ultimate strength, endurance strength, and impact strength respectively should be considered for design purpose. Deficient material selection can occur due to reliance on tensile data for selection of materials, and inability to select of metal in light of the expected failure mechanism and so as to develop suitable criteria for the design purpose. The problem of the materials selection is further complicated when the performance of materials varies as function of time, e.g. creep, corrosion, embrittlement, etc. The criteria for the selection of metal for designing a component for a particular service conditions must be based on the expected failure mechanism.