Search Results for spinodal transformation structures

This chapter explains how the presence of intermediate phases affects the melting behavior of binary alloys and the transformations that occur under different rates of cooling. It begins by examining the phase diagrams of magnesium-lead and copper-zinc, noting some of the complexities associated with intermediate phases. It then discusses the difference between ordered and disordered phases and how they are accounted for on phase diagrams. It describes how the atoms in a disordered solution may arrange themselves into an ordered array, forming a superlattice in the process of cooling, and goes on to identify the most common superlattice structures and their corresponding alloy phases. It also discusses the factors that limit the formation of superlattices along with the kinetics of spinodal decomposition and its effect on microstructure development.

This chapter provides a short introduction to phase transformations, namely, the liquid-to-solid phase transformations that occur during solidification and the solid-to-solid transformations that are important in processing, such as heat treatment. It also introduces the concept of free energy that governs whether or not a phase transformation is possible, and then the kinetic considerations that determine the rate at which transformations take place. The chapter also describes important solid-state transformations such as spinodal decomposition and martensitic transformation.

Nonferrous alloys are heat treated for a variety of reasons. Heat treating can reduce internal stresses, redistribute alloying elements, promote grain formation and growth, produce new phases, and alter surface chemistry. This chapter describes heat treatment processes and how nonferrous alloys respond to them. It provides information on aluminum, cobalt, copper, magnesium, nickel, and titanium alloys and their composition, microstructure, properties, and processing characteristics.

The term heat treatable alloys is used in reference to alloys that can be hardened by heat treatment, and this chapter briefly describes the major types of heat treatable nonferrous alloys. The discussion provides a general description of annealing cold-worked metals and describes some of the common nonferrous alloys that can be hardened through heat treatment. The nonferrous alloys covered include aluminum alloys, cobalt alloys, copper alloys, magnesium alloys, nickel alloys, and titanium alloys.

The appendix provides a glossary of practical heat treating terms.

This chapter explains the significance of the phase diagram and its use in the development of new materials. The chapter describes the basic rules of heterogeneous equilibrium, presents a comparison between liquidus line and solidus line, and provides information on the solubility curve and the binodal curve.

This chapter discusses the basic principles of precipitation hardening, an important strengthening mechanism in nonferrous alloys as well as stainless steel. It begins with a detailed review of the theory of precipitation hardening, then describes its application to aluminum alloys and nickel-base superalloys.

This chapter explains the distinction between materials and matter through the concept of microstructure. It presents the history of matter science and the establishment of metallography. The chapter provides an overview of the progress of steel technology, progress in synthetic polymers and ceramics, and establishment and development of materials science.

This chapter presents definitions of terms related to the metallurgy and metallographic study of irons and steels.

This chapter provides a detailed discussion on the Brownian motion, diffusion coefficient , and Fick's diffusion laws. It presents a review of solid phase diffusion and discusses the mechanism of diffusion and diffusion coefficient.

Stainless steels derive their name from their exceptional corrosion resistance, which is attributed to their finely tuned compositions. This chapter discusses the alloying elements used in stainless steels and the some of the processing challenges they present. One of the biggest challenges is that stainless steels cannot be hardened by heat treatment. As a result, they are highly sensitive to processing-induced defects and the formation of detrimental phases. The chapter explains how alloy design, phase equilibria, microstructure, and thermomechanical processing can be concurrently optimized to produce high-quality austenitic, ferritic, and duplex stainless steels.

Diffusion is the movement of atoms through the crystalline lattice. This chapter discusses the two main types of diffusion that can occur in solids: interstitial diffusion and substitutional diffusion. It describes Fick's first and second laws of diffusion, with emphasis on several applications of the latter. The chapter also provides information on the temperature dependence of diffusion, intrinsic diffusion coefficients (Kirkendall effect), and high diffusion paths.

This chapter discusses the alloy composition, metallurgy, mechanical behavior, stabilization, texture, anisotropy, high-temperature properties, and corrosion and oxidation resistance of ferritic stainless steels.

This chapter discusses the composition and classification of stainless steels and focuses on the processes involved in heat treatment and applications of these steels. The wrought and the cast stainless steels covered are ferritic, austenitic, duplex (ferritic-austenitic), martensitic, and precipitation-hardening. In addition, information on special considerations for stainless steel castings is also provided. The heat treatment processes explained in the chapter are preheating, annealing, stress relieving, hardening, tempering, austenite conditioning, heat aging, and nitride surface hardening. Finally, some special considerations for stainless steel castings are discussed.

Stainless steel base metals and the welding filler metals used with them are chosen on the basis of suitable corrosion resistance for the intended application. This article describes several constitution diagrams that that have been developed to predict microstructures and properties. This is followed by discussions of weldability, cracking, and the engineering properties of stainless steel welds, namely martensitic stainless steels, ferritic stainless steel welds, austenitic stainless steels, and duplex stainless steels.

This chapter provides information on the structure, design aspects, mechanical properties, forming, machining, and corrosion resistance characteristics of duplex stainless steels. The different types of corrosion covered are general corrosion, pitting corrosion, crevice corrosion, and stress corrosion cracking.