Tham khảo tài liệu 'mechanical properties of engineered materials 2008 part 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 2 Defect Structure and Mechanical Properties INTRODUCTION Since the mechanical behavior of solids is often controlled by defects a brief review of the different types of defects is presented in this chapter along with the indicial notation that is often used in the characterization of atomic planes and dimensions. The possible defect length scales are also discussed before presenting a brief introduction to diffusion-controlled phase transformations. Finally an overview of the mechanical behavior of materials is presented in an effort to prepare the reader for more detailed discussion in subsequent chapters. The material described in this chapter is intended for those with limited prior background in the principles of materials science. The better prepared reader may therefore choose to skim this chapter and move on to Chap. 3 in which the fundamentals of stress and strain are presented. INDICIAL NOTATION FOR ATOMIC PLANES AND DIRECTIONS Abbreviated notation for the description of atomic planes and directions are presented in this section. The so called Miller indicial notation is presented Copyright 2003 Marcel Dekker Inc. first for cubic lattices. This is followed by a brief introduction to Miller-Bravais notation which is generally used to describe atomic planes and directions in hexagonal closed packed structures. Miller Indicial Notation Miller indicial notation is often used to describe the planes and directions in a cubic lattice. The Miller indices of a plane can be obtained simply from the reciprocal values of the intercepts of the plane with the x y and z axes. This is illustrated schematically in Figs and . The reciprocals of the intercepts are then multiplied by appropriate scaling factors to ensure that all the resulting numbers are integer values corresponding to the least common factors. The least common factors are used to represent the Miller indices of a plane. Any negative numbers are represented by bars over them. A single .
