This article provides a detailed discussion on nanoindentation hardness, high-strain-rate behavior and strain-rate sensitivity, and corrosion response of additively manufactured (AM) metals. It summarizes the most commonly used AM alloys for applications in harsh environments and their respective corrosion responses in various service environments. It also provides several case studies on location-dependent properties, microstructural evolution, and indentation strain-rate sensitivity of various additively manufactured alloys.

Heat treatment of aluminum alloys is assessed by various quality-assurance methods that include metallographic examination, hardness measurements, mechanical property tests, corrosion-resistance tests, and electrical conductivity testing. The use of hardness measurements in the quality assurance of heat treated aluminum products is effectively used in conjunction with the measurement of surface electrical conductivity. This article provides a detailed discussion of the error sources in eddy-current conductivity measurements. It also presents useful information on the variation of electrical conductivity of alloy 2024 samples as a function of aging time at different isothermal holding temperatures.

Hardness conversions are empirical relationships that are defined by conversion tables limited to specific categories of materials. This article is a comprehensive collection of tables that list hardness conversion formulas. Approximate Rockwell B and C hardness conversion numbers for nonaustenitic steels, and approximate equivalent hardness numbers for Brinell and Vickers (diamond pyramid) hardness numbers for steels are provided.

Hardenability refers to the ability of steel to obtain satisfactory hardening to some desired depth when cooled under prescribed conditions. It is governed almost entirely by the chemical composition (carbon and alloy content) at the austenitizing temperature and the austenite grain size at the moment of quenching. This article describes the Jominy end-quench test, the Grossman method, and the air hardenability test to evaluate hardenability. It also reviews the factors that influence steel hardenability and selection.

Hardness conversions are empirical relationships that are defined by conversion tables limited to specific categories of materials. This article tabulates examples of the published hardness conversion equations for various materials including steels, cement carbides, and white cast irons. It informs that when making hardness correlations, it is best to consult ASTM E 140. The article tabulates the approximate Rockwell B hardness and Rockwell C hardness conversion numbers for nonaustenitic steels according to ASTM E 140. It also tabulates the approximate equivalent hardness numbers for Brinell hardness numbers and Vickers (diamond pyramid) hardness numbers for steel.

This article is a comprehensive collection of tables that list the approximate equivalent hardness numbers for wrought aluminum products, wrought coppers, and cartridge brass.

Hardness conversions are empirical relationships that are defined by conversion tables limited to specific categories of materials. This article summarizes hardness conversion formulas for various materials in a table. It tabulates the approximate Rockwell B and Rockwell C hardness conversion numbers for nonaustenitic steels. The article lists the approximate equivalent hardness numbers for Brinell hardness numbers and Vickers hardness numbers for steel in tables. The tables are also outlined in a graphical form.

This article presents a comprehensive collection of tables that list Rockwell hardness and superficial hardness numbers for wrought aluminum products, wrought coppers, and cartridge brass.

Hardness conversions are empirical relationships defined by conversion tables limited to specific categories of materials. This article is a collection of tables that present approximate Rockwell B hardness conversion numbers for nonaustenitic steels as per ASTM E 140 and approximate equivalent hardness numbers for the Brinell hardness and the Vickers (diamond pyramid) hardness numbers for steel.

This article describes the principal methods for macroindentation hardness testing by the Brinell, Vickers, and Rockwell methods. For each method, the test types and indenters, scale limitations, testing machines, calibration, indenter selection and geometry, load selection and impression size, testing methodology, and testing of specific materials are also discussed.

Hardness characterizes the resistance of the ceramic to deformation, densification, displacement, and fracture. It is usually measured with conventional microindentation hardness machines using the Knoop or the Vickers diamond indenters. This article discusses the metrology issues of the Knoop and the Vickers hardness in ceramics. It explicates how to estimate fracture toughness from Vickers indentation cracking. The article also provides information on instrumented hardness testing and the Meyer law.

This article reviews the factors that have a significant effect on the selection and interpretation of results of different hardness tests, namely, Brinell, Rockwell, Vickers, and Knoop tests. The factors concerned include hardness level (and scale limitations), specimen thickness, size and shape of the workpiece, specimen surface flatness and surface condition, and indent location. The article focuses on the selection for specific types of materials, such as steels, cast irons, nonferrous alloys, and plastics, and industrial applications, of hardness tests.

This article is a comprehensive collection of tables that list the values for hardness of plastics, rubber, elastomers, and metals. The tables also list the tensile yield strength and tensile modulus of metals and plastics at room temperature. A comparison of various engineering materials, on the basis of tensile strength, is also provided.

Hardness testing is perhaps the simplest and the least expensive method of mechanically characterizing a material. This article provides an overview of the principles of hardness testing. It compares Brinell with Meyer hardness testing and hardness testing of fully cold worked metals with fully annealed metals. The article discusses the plastic deformation of ideal plastic metals under an indenter, by a flat punch, and by spherical indenters. The classification of the hardness tests using various criteria, including type of measurement, magnitude of indentation load, and nature of the test, is also provided.

This article provides a discussion on the equipment used and specimen preparation for microindentation hardness testing (MHT) such as the Vickers hardness test and the Knoop hardness test. It describes the important test considerations to be considered during MHT. The article also discusses the most common hardness conversions and the applications of MHT.

Miscellaneous hardness tests encompass a number of test methods that have been developed for specific applications. These include dynamic, or "rebound," hardness tests using a Leeb tester or a Scleroscope; static indentation tests on rubber or plastic products using the durometer or IRHD testers; scratch hardness tests; and ultrasonic microindentation testing. This article reviews the procedures, equipment, and applications associated with these alternate hardness test methods.

The gage repeatability and reproducibility (GRR) study is a procedure for determining the repeatability of a test instrument and the reproducibility of a specific gage in operation. This article reviews the general method of GRR studies and its application for indentation hardness testing. It describes a long method and a short method for evaluation of GRR. The article analyzes factors of hardness testing instruments and provides guidelines for hardness tests. It concludes with a list of suggestions that can improve hardness tests.

A newly developed theory on plasticity makes it possible to include elastic effects, which play a major role when using blunt hardness indenters. This article reviews the new theory and explains several phenomena associated with practical hardness testing. In the indentation hardness test, a blunt indenter that approximates a flat punch is forced into a plane surface. The effective cone angle for most indenters is such that some upward flow results even when there is sufficient material surrounding the indenter to provide a full elastic constraint. When loaded by a blunt indenter, materials with high values of Young's Modulus of Elasticity/uniaxial flow stress (E/Y) (metals) appear to develop a Hertzian stress distribution over the contact. In contrast, materials with low values of E/Y (glasses and polymers) develop a uniform distribution of stress.

Hard chromium plating is produced by electrodeposition from a solution containing chromic acid and a catalytic anion in proper proportion. This article presents the major uses of hard chromium plating, and focuses on the selection factors, plating solutions, solution and process control, equipment, surface preparation, and crack patterns and other characteristics of hard chromium plating. It offers recommendations for the design and use of plating racks, describes the problems encountered in hard chromium plating, and their corrective procedures. The article provides information on the removal of chromium plate from coated metals, recovery and disposal of wastes, and stopoff media for selective plating.

This article discusses the corrosion of chromium electrodeposits and the ways for optimizing corrosion resistance. It describes the processing steps and conditions for hard chromium plating. These steps include pretreatment, electroplating, and posttreatment. The article also provides information on duplex coatings and the applications of chromium electrodeposits.