Atomic-scale modeling of dislocations and related properties in the hexagonal-close-packed metals
- PDF / 1,453,608 Bytes
- 13 Pages / 612 x 792 pts (letter) Page_size
- 24 Downloads / 198 Views
INTRODUCTION
CURRENT research into the physical metallurgy of metals with the hcp crystal structure arises in part from the wide variety of mechanical and physical properties they exhibit. Understanding the links between the atomic processes, the microstructure, and properties can open the way for new applications of these materials. After decades of study, many issues remain unresolved, but the development of more powerful computational and experimental techniques has now led to a resurgence of interest in this field, as demonstrated by the articles presented in this special issue. One of the topic areas where new work is most apparent is plastic deformation. As discussed in the accompanying overview by Yoo et al.,[1] the deformation characteristics arising from response to changes in stress and temperature, even for the same metal, are complex, and modeling of dislocations, planar faults, and deformation twins on the atomic scale is crucial to understanding how the various deformation modes occur and what controls them. The same point can be made for other features shown by these metals. D.J. BACON, Professor, is with Materials Science and Engineering, Department of Engineering, The University of Liverpool, Liverpool L69 3GH, United Kingdom. Contact e-mail: [email protected] V. VITEK, Professor, is with the Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, PA 19104. This article is based on a presentation made in the symposium entitled “Defect Properties and Mechanical Behavior of HCP Metals and Alloys” at the TMS Annual Meeting, February 11–15, 2001, in New Orleans, Louisiana, under the auspices of the following ASM committees: Materials Science Critical Technology Sector, Structural Materials Division, Electronic, Magnetic & Photonic Materials Division, Chemistry & Physics of Materials Committee, Joint Nuclear Materials Committee, and Titanium Committee. METALLURGICAL AND MATERIALS TRANSACTIONS A
The purpose of the present article is to highlight recent progress in atomic-scale computer simulation in three areas, namely, the core structure of dislocations responsible for the primary slip modes in metals such as ␣ -titanium (Ti) and ␣ -zirconium (Zr); the structure and mobility of twinning dislocations; and the nature and properties of the defects created by radiation damage. These topics will be presented and discussed in Sections II through IV, respectively. We aim to emphasize the real advances made since publication of our articles on these topics at an earlier conference devoted to research on defects in the hcp metals.[2,3,4] The computation techniques used are dealt with in the articles cited herein. In summary, atomic interactions and displacements are computed using either molecular statics or molecular dynamics (MD), corresponding to either minimization of the crystalpotential energy alone or computation of both the kinetic and potential energy contributions. Over the past decade, empirical short-range, many-body potentials have been used in the main to describ
Data Loading...
