Origins of directional mechanical properties

Abstract

The origins of the directional properties of a solid are in the patterns of arrangement of the components of its structure, but mechanical properties have to be defined in terms of measurements made in mechanical tests. More explicitly, one should speak of directional behaviour, since the mechanical effects of structural directionality depend on the conditions of stressing. In ordinary wrought metals there are usually several different superimposed patterns of directional structural arrangement which occur on widely different scales and the effects of which combine to influence macroscopic mechanical behaviour. Thus, the establishment of a comprehensive theory of directional structure-mechanical property relationships is a highly complex task. Necessarily, this broad problem has been divided into a number of separate areas of study which are the concern of different groups of investigators, so that the subject tends to be fragmented, and the practitioner is faced with a problem of synthesis. In this review an attempt is made to outline the context of each of the main areas of study and to highlight some of the more notable recent advances, towards better understanding of directional structure-mechanical property relationships in wrought metals and towards improved control and useful exploitation of such directionality.