Fatigue and Fracture Characteristics of High-Hardness, Laminar Composite Steel
SourceThe purpose of the present paper is to characterize static and dynamic mechanical properties of high-hardness laminar composite steel. Tensile, compressive, and shear properties were obtained. Fatigue properties were also investigated including the effect of minimum: maximum stress (R) ratio, humidity, and surface condition. Improving the as-received surface led to increased values of the fatigue limit. Fatigue resistance was lowered markedly by humidity. For a given value of maximum stress increasing the R ratio increased the number of cycles to failure. Orientation had a pronounced effect on the toughness of cracked and uncracked Charpy specimens, that is, RW orientation exhibited greater toughness than did WR. There is some evidence to indicate that constraint has caused the hard-soft interfacial bond to delaminate. Lastly, examination of the fracture surfaces of the tensile, fatigue, and Charpy specimens revealed that in most instances crack initiation phase of fracture takes place on the hard side of the composite.