Search Results for test

The organizations that are most active in the development of standards for powder metallurgy (PM) are the American Society for Testing and Materials (ASTM), Metal Powder Industries Federation (MPIF), and International Standards Organization (ISO). This article presents the test method standards, materials standards, and material designation codes for PM materials. It provides information on the codes for structural parts, PM soft magnetic materials, PM self-lubricating bearings, metal injection molded materials, and powder forged materials.

This article discusses the factors to be considered in selecting and evaluating machining tests for the purpose of evaluating cutting tool performance and workpiece machinability. It provides a brief description of cutting tool materials, such as high-speed steels, uncoated and coated carbides, cermets, ceramics, cubic boron nitride, and polycrystalline diamond. The article considers the matrices that represent the range of tests performed on candidate cutting tool materials: the workpiece matrix, the property matrix, and the operation matrix. Various machine tests used to evaluate cutting tools, including the impact test, turning test, and facing test, are described. The article lists the factors to be taken into consideration in measuring the machinability of a material. The article presents general recommendations for proper chip groove selection on carbide tools and concludes with information on machining economics.

This article details factors that have been used for evaluating the susceptibility of alloys to stress-corrosion cracking. Many considerations impacting the validity and accuracy of information gathered from laboratory testing programs are reviewed. The article highlights the main characteristics of probability distributions, such as normal distribution, log-normal distribution, exponential distribution, Poisson distribution, and extreme-value distribution. It also provides information on the statistical concepts to produce effective test programs.

A test plan specifies material properties to be evaluated, selects test methods, eliminates options offered by standard test methods by selecting specific specimen and test configurations, and defines success criteria. This article discusses various testing objectives that affect the execution of testing programs. The testing objectives include development of test matrices, testing standards, specimen preparation, environmental conditioning, instrumentation and data acquisition, failure modes, and data interpretation and recording.

This article discusses several alternative mechanical test approaches that can be applied to additive manufacturing (AM) materials, both for smaller-scale assessments and for specimens that have been extracted from an AM component. This includes small punch testing, shear punch testing, and small ring testing.

This article introduces the principal methodologies and some technologies that are being applied for nondestructive evaluation of composite materials. These include ultrasonic testing (UT), air-coupled UT, laser UT, ultrasonic spectroscopy, leaky lamb wave method, acousto-ultrasonics, radiography, X-ray computed tomography, thermography, low-frequency vibration methods, acoustic emission, eddy current testing, optical holography, and shearography. The article presents some examples are for fiber-reinforced polymer-matrix composites. Many of the techniques have general applicability to other types of composites such as metal-matrix composites and ceramic-matrix composites.

This article presents a summary of the chemical fundamentals, general techniques, limitations, and applications of chemical spot testing as well as a brief overview of innovations and specialized applications. A list of selected reagents, including abbreviated instructions for preparing the reagent solution(s), for performing the spot test, and for interpreting the results, is also included. The article discusses two specialized applications of qualitative analysis, namely illicit drug identification and spacecraft drinking water quality testing. It also contains tables listing common presumptive tests for detecting anions and cations in aqueous solution.

Mechanical and environmental loadings cause a variety of failure modes in composites, including matrix cracking, fiber-matrix debonding, delamination between plies, and fiber breakage. This article summarizes visual analysis and nondestructive testing methods for the failure analysis of composites. These methods include radiography, ultrasonic techniques, acoustic emission, and thermograph. The article also provides information on destructive test techniques.

This article provides an overview of common analytical tools used as part of the process of providing practical information regarding the causes of a coating problem or failure. The common analytical tools include Fourier transform infrared spectroscopy, differential scanning calorimetry, scanning electron microscopy-energy dispersive X-ray spectroscopy, chromatography, and electrochemical impedance spectroscopy. Test cabinets and standard test environments for laboratory analysis are reviewed. The article describes non-standard simulation testing and case studies of simulated environments for coating failure analysis.

This article describes the two commonly used standardized tests for determining the mechanical properties of thermal spray coatings: hardness testing and tensile adhesion testing. It discusses the destructive and non-destructive methods of residual-stress measurement. Electrochemical testing methodologies include two distinctly different methods: direct and alternating current impedance techniques for assessing the corrosion resistance of coating attributes. The article also reviews the testing methods for determining thermomechanical and environmental stability of thermal barrier coatings. It discusses the wear testing methodologies that are standardized by ASTM, including the pin-on-disk, block-on-ring, dry sand/rubber wheel, erosion, metallographic apparatus abrasion, fretting wear, cavitation, reciprocating ball-on-flat, impact, and rolling contact fatigue test. The article concludes with a discussion on the methods of testing abradability and erosion resistance in abradable coatings.

Thermomechanical are used to gain insight into the causes of problems that arise during a given thermomechanical process. This article provides examples to demonstrate how significant the parameters were selected for specific tests. It examines the types of problems that can occur during a thermomechanical process. The article provides information on the thermophysical properties, which include specific heat, coefficient of thermal expansion, thermal conductivity/diffusivity, and density. It concludes with examples that illustrate how the various considerations in testing are successfully used to solve practical thermomechanical processing problems.

Immersion testing is the most frequently conducted test for evaluating corrosion of metals in aqueous solutions. This article focuses on the basic factors that are considered in different conditions of immersion testing. These factors are solution composition, temperature, aeration, volume, velocity, and waterline effects; specimen surface preparation; method of immersion of specimens; duration of test; and method of cleaning specimens. The article discusses the different conditions of immersion testing, namely, full immersion condition, high temperature condition, partial immersion and vapor phase condition, and alternate immersion condition. It concludes with a checklist of items that should be included in a standard report of immersion tests.

This article discusses the applications and use of salt spray (fog) testing used to test the resistance of aluminum alloys to exfoliation corrosion. There are two basic types of salt-spray/fog corrosion tests: static condition tests and cyclic condition tests. The article provides a discussion of these tests and indicates the significant differences in each type test used in the combination of weathering and corrosion testing procedures. It also provides information on the test specimen preparation for spray (fog) corrosion tests. Industry specific standards for test specimen procedures often reference the ASTM standards as a basis. The article includes various ASTM standards that describe several cleaning procedures used prior to testing. It describes the major components of a corrosion test chamber.

This article provides an overview of two major classes of bearings: rolling bearings and sliding, or plain, bearings. It reviews the experimental data resulted from testing of rolling and sliding bearing materials with illustration. The article presents a table that summarizes rolling contact fatigue test methods that ASTM published in STP 771. It also describes the role of lubrication in the bearings.

This article describes measurement techniques for the three basic types of adhesion: fundamental adhesion, thermodynamic adhesion, and practical adhesion. It discusses common measurement methods for each type of adhesion with the main focus on practical adhesion testing of coatings and thin films. The article provides an insight into the mechanisms of environmentally induced interfacial degradation by discussing the fundamental aspects of adhesion between two dissimilar materials. It examines the use of adhesion tests in the evaluation of stress-corrosion cracking within bimaterial interfaces. Testing techniques for <i>in situ</i> environmental testing of thin-film adhesion are also reviewed.

This article reviews the origins and development of scratch tests, the experimental configurations used in these tests, and the application of the tests to characterize the mechanical response of materials. It provides information on the measurement of indentation hardness. The article describes the important parameters of the scratch test. Finally, it discusses the sliding indentation fracture process of brittle materials.

Bend tests are conducted to determine the ductility or strength of a material. This article discusses the different bend tests with emphasis on test methods, apparatuses, procedures, specimen preparation, and interpretation and reporting of results. The types of bend tests discussed are bending ductility tests, bending strength tests (ASTM E 855), bend tests as per EN 12384 and JIS 3130, and computer-aided bending tests. The three standard bending strength tests are the cantilever beam bend test, the three-point bend test, and the four-point bend test. European Standard EN 12384 specifies a bend test to determine the modulus of elasticity in bending. Japanese Industrial Standard JIS 3130 specifies two tests to determine the elastic limit of spring plate or strip: the repeated deflection spring test and the moment type spring test.

Leak testing is used to determine the rate at which a liquid or gas penetrates from inside a component or assembly to the outside, or vice versa. This article discusses the type of leaks, namely real leaks, and virtual leaks. It describes the leak testing of fluid systems at pressure through acoustic method and bubble testing. The article gives a short note on types of leak detectors, sulfur hexafluoride detectors and mass-spectrometer. It tabulates the pressure and vacuum system leak-testing methods and discusses the application of gas detectors in leak testing.

This article reviews the various types of mechanical testing methods, including hardness testing; tension testing; compression testing; dynamic fracture testing; fracture toughness testing; fatigue life testing; fatigue crack growth testing; and creep, stress-rupture, and stress-relaxation testing. Shear testing, torsion testing, and formability testing are also discussed. The discussion of tension testing includes information about stress-strain curves and the properties described by them.

Wear is mechanically-induced surface damage that results in the progressive removal of material. Because different types of wear occur in machinery, many different types of wear tests have been developed to evaluate its effects on materials and surface treatments. This article provides an explanation on mechanisms, forms (sliding, impact, and rolling) and the causes of wear. It describes the wear measuring methods, including the mass loss method, wear width method, and scar depth method. The units used to report wear vary with type of wear and with the purpose for which the data are to be used. Listing the considerations of tribosystem analysis, the article provides information on selection of ASTM wear test methods grouped by wear type. The article concludes by tabulating the testing geometries and parameters that are commonly controlled and reported when conducting wear tests.