Search Results for alloy

Nickel-base alloys can be machined by techniques that are used for iron-base alloys. This article discusses the effects of distortion and microstructure on the machinability of nickel alloys. It tabulates the classification of nickel alloys based on machining characteristics. The article describes the machining operations performed on nickel alloys, such as turning, planing and shaping, broaching, reaming, drilling, tapping and threading, milling, sawing, and grinding. It provides information on the cutting fluids used in the machining of nickel alloys. The article also analyzes nontraditional machining methods that are suitable for shaping high-temperature, high-strength nickel alloys. These include electrochemical machining, electron beam machining, and laser beam machining.

The process of making assemblies of solid-solution and precipitation hardening groups of alloys and superalloys often requires welding of dissimilar metals, welding of diffusion-bonded materials, and sometimes weld overlay cladding and even thermal spraying that in turn requires special knowledge and treatments developed specifically for each material. This article emphasizes the special metallurgical welding considerations for welding solid-solution and precipitation hardening nickel alloys, cobalt alloys, and superalloys.

Nickel alloys can be joined reliably by all types of welding processes or methods, with the exception of forge welding and oxyacetylene welding. This article discusses the heat treatment of nickel alloys and tabulates nominal compositions of selected weldable wrought nickel and nickel alloys. It provides information on gas-tungsten arc welding, gas-metal arc welding, plasma arc welding, shielded metal arc welding, and submerged arc welding for welding nickel alloys. The article reviews the defects encountered in the arc welding of nickel alloys, including porosity, cracking, and stress-corrosion cracking. It provides information on the factors that influence the choice of filler metal and welding process of nickel alloys.

Oxide - dispersion - strengthened (ODS) materials utilize extremely fine oxide dispersion for strengthening, such as nickel-base alloys or alumina. The processing techniques employed in the production of ODS alloys produce some entrapped gases, which tend to create porosity during welding that can be rectified by suitable designing considerations. This article discusses certain successful design strategies employed in joining ODS alloys in consideration with the grain structure. It further provides a brief discussion on different welding processes involved in joining ODS materials, namely, gas-tungsten arc welding, gas-metal arc welding, electron-beam and laser-beam welding, resistance welding, furnace brazing, friction welding, and explosion welding.

This article discusses the history of shape memory alloys (SMAs) along with their properties, capabilities, and crystallography, including phase transformations that occur during thermal treatment. It describes the thermomechanical behaviors of SMAs and explains how to characterize them using differential scanning calorimeter (DSC) techniques as well as other methods. The article examines the most common shape memory alloys, namely, nickel-titanium and copper-base SMAs, and provides information on their respective properties.

Nickel in elemental form or alloyed with other metals and materials has made significant contributions to our present-day society and promises to continue to supply materials for a demanding future. This article provides a historical overview and physical metallurgy of nickel and nickel alloys. It lists and describes the compositions, mechanical and physical properties, and applications of commercial nickel and its alloys. The article briefly explains the forms of corrosion resulting from the exposure of nickel alloys to aqueous environments. It provides valuable information on the commercial forms of nickel alloys, namely, nickel-copper alloys, nickel-chromium and nickel-chromium-iron series, iron-nickel-chromium alloys, controlled-expansion alloys, nickel-iron low-expansion alloys, soft magnetic alloys, and welding alloys.

Oxide dispersion-strengthened (ODS) alloys are produced by mechanical alloying, a process by which base metals and alloying particles are powdered together forming a metal-matrix composite. This article discusses the production of ODS superalloy powders and subsequent processing steps, including consolidation, hot rolling, heat treating, and the fabrication of mill products. It also discusses the nominal composition and microstructure of commercial ODS alloys, including nickel, iron, and aluminum-base systems, and provides detailed information on their mechanical, physical, oxidation, and hot-corrosion properties.

Electrical resistance alloys include those types used in instruments, control equipment, heating elements, and devices that convert heat generated to mechanical energy. This article discusses the basic classification of electrical resistance alloys (resistance alloys, heating alloys, and thermostat metals), their subtypes, properties, service life, and operating temperatures. It describes the designing and fabrication of open resistance and sheathed heaters. The article contains a collection of tables and graphs that provide information on the mechanical properties, chemical composition, temperature coefficient of resistance, furnace operating temperatures, length and spacing of loops, ribbon size, and electrical capacity of heating elements.

This article discusses the corrosion characteristics of superaustenitic stainless and duplex stainless steels, which are used in pharmaceutical industry. It describes passivation treatments and the electropolishing of stainless steels. The article informs that electropolishing is not a passivation treatment, although the proper execution of the process will result in a passive surface. The article concludes with a discussion on roughing, which is a phenomenon of particular interest to the pharmaceutical industry.

Refractory metals are extracted from ore concentrates or scrap, processed into intermediate chemicals, and then reduced to metal, usually in powder form. This article discusses the raw materials needed and the processing steps for producing pure and alloyed refractory metal powders. The effects of processing conditions on the physical and chemical properties of tungsten, molybdenum, tantalum, niobium, and rhenium powders are reviewed.

This article focuses on the selection, properties, and applications of powder metallurgy refractory metals and their alloys, including tungsten, molybdenum, tantalum, niobium, and rhenium.

This article focuses on the forging characteristics of different types of refractory metals and alloys, namely, niobium and niobium alloys, molybdenum and molybdenum alloys, tantalum and tantalum alloys, and tungsten and tungsten alloys.