Complex characteristics of the mechanical properties of metals

Abstract

The method of computation of o n is based on two limiting states of the material: a completely brittle material for which ~ = 0, and a completely viscous material for which 9 = 1 (100%). In the first case, which can be called "decohesion," the specimen fails by tearing under the action of normal stresses. In this case, the decohesion indicator K 4 = 1 -~, where } is reckoned in fractions of a unit. In the second case, the specimen is failed by shearing under the action of shear stresses. This process can be called "cohesion": The cohesion indicator K = 9. The elastoplastic state of real structural alloys is intermediate between these two ~imiting states, and can be characterized by a certain parameter relating both indicators -K d and K c. This parameter, however, cannot assume the form of the ratios Kj/K~, or K /K., since they are meaningless when ~ = 0, and ~ = 1 Neither can the indicator Q ~ e Q ° (K d + Kc)/2 be used, since it is 0.5 for any value of 4. It is therefore proposed that the product Kel a = KdK c = 4(1 -~), which varies as is shown in Fig. 1 as ~ increases from 0 to i, be employed as this parameter. Let us call it the elasticity indicator.