Search Results for hot deformation

Any model that describes the early stage of cavitation must therefore address experimental observations of continuous nucleation, cracklike interface cavities, cavity growth from nanometer-scale sizes, and debonding at particle interfaces and formation of large-faceted cavities. This article summarizes the microstructural details of the early stages of cavitation in metals for understanding the interface-constrained plasticity cavitation model. It discusses formulation, predictions and implications, involved in analysis of cavitation under constrained conditions.

This article provides a discussion on forging methods, melting procedures, forging equipment, forging practices, grain refinement, and critical factors considered in forging process. It describes the different types of solid-solution-strengthened and precipitation-strengthened superalloys, namely, iron-nickel superalloys, nickel-base alloys, cobalt-base alloys, and powder alloys. The article discusses the microstructural mechanisms during hot deformation and presents processing maps for various superalloys. It concludes with a discussion on heat treatment of wrought heat-resistant alloy forgings.

Recrystallization is to a large extent responsible for their final mechanical properties. This article commences with a discussion on static recrystallization (SRX) and dynamic recrystallization (DRX). The DRX includes continuous dynamic recrystallization (CDRX) and discontinuous dynamic recrystallization (DDRX). The article discusses the assumptions and simplifications for the Avrami analysis. It describes the effects of nucleation and growth rates on recrystallization kinetics and recrystallized grain size based on the Johnson-Mehl-Avrami-Kolmogorov model for static recrystallization. The article reviews the kinetics of DRX with the aid of the Avrami relations. It considers the basic framework of the mesoscale approach for DDRX, including the three basic equations for grain size changes, strain hardening and dynamic recovery, and nucleation. The article explains the mesoscale approach for CDRX to predict microstructural evolutions occurring during hot deformation, along with an illustration of the main features of the CDRX mesoscale model.

Thermomechanical processing (TMP) refers to various metal forming processes that involve careful control of thermal and deformation conditions to achieve products with required shape specifications and good properties. This article describes TMP methods in producing hot-rolled steel and reviews how improvements in the strength and toughness depend on the synergistic effect of microalloy additions and on carefully controlled thermomechanical conditions. It discusses TMP variables and the general distinctions between conventional hot rolling and common types of controlled-rolling schedules. The article describes the metallurgical processes in grain refinement of austenite steel by hot working, such as recovery and recrystallization and strain-induced transformation. The grain refinement in high strength low alloy steel by alloy addition is also discussed. The article provides an outline on the key stages of deformation, and the required metallurgical information at each of these stages.

The warm and hot working of metals provide the ability to shape important materials into component shapes that are useful in a variety of applications requiring strength, toughness, and ductility. This article focuses on a variety of metals that can be hot or warm worked, and describes the characteristics and processing considerations of each metal. It discusses forging because it is a versatile metalworking process and performed at cold, warm, and hot working temperatures. The article also presents the applications of steels, stainless steels, aluminum alloys, titanium alloys, superalloys, and copper alloys.

This article describes the use of compression tests, namely, cylindrical compression, ring compression, and plane-strain compression tests at elevated temperatures. It discusses the effects of the temperature, strain rate, and deformation heating on metals during the cylindrical compression test, with the help of flow curves. The article illustrates the testing apparatus used in the cylindrical compression test. It describes the issues regarding friction and temperature, and strain-rate control with proper test equipment and experimental planning during the ring compression test and plane-strain compression test. The article also reviews the testing conditions, procedures, and advantages of hot plane-strain compression test.