This article focuses on mechanical behavior of materials under conditions of uniaxial tension and compression. The emphasis is on mechanical behavior during the engineering tension test, which is used to provide basic design information on the strength of materials and as an acceptance test for the specification of materials. The article presents mathematical expressions for a flow curve of many metals in the region of uniform plastic deformation. It explains that the rate at which strain is applied to the tension specimen has an important influence on the stress-strain curve. The point of necking at maximum load can be obtained from the true stress-true strain curve by finding the point on the curve having a subtangent of unity. The article concludes with an overview of the ductility measurements performed by notch tensile and compression tests.

This article discusses the concepts underlying linear elastic fracture mechanics and elastic-plastic fracture mechanics as well as their importance in characterizing the fracture behavior of the high-strength aluminum alloys. It describes the three methods used for analyzing elastic-plastic fracture, namely R-curve concept, J-integral concept, and crack tip opening displacement method. The article considers the primary measures used to assess the toughness of aluminum alloy castings and wrought alloys: notch toughness, tear resistance, and plane-strain fracture toughness.

This article is an atlas of fractographs that helps in understanding the causes and mechanisms of fracture of AISI/SAE alloy steels (4xxx steels) and in identifying and interpreting the morphology of fracture surfaces. The fractographs illustrate the brittle fracture, ductile fracture, impact fracture, fatigue fracture surface, reversed torsional fatigue fracture, transgranular cleavage fracture, rotating bending fatigue, tension-overload fracture, torsion-overload fracture, slip band crack, crack growth and crack initiation, crack nucleation, microstructure, hydrogen embrittlement, sulfide stress-corrosion failure, stress-corrosion cracking, and hitch post shaft failure of these steels. The components considered in the article include tail-rotor drive-pinion shafts, pinion gears, outboard-motor crankshafts, bull gears, diesel engine bearing cap bolts, splined shafts, aircraft horizontal tail-actuator shafts, bucket elevators, aircraft propellers, helicopter bolts, air flasks, tie rod ball studs, and spiral gears.

This article is a compilation of terms related to mechanical testing and evaluation of metals, plastics, ceramics, and composites.

A wide range of mechanical properties can be obtained with a given composition of cast iron, depending on the microstructural constituents that form during solidification and subsequent solid-state processing. This article discusses the mechanical properties of gray iron and provides some general property comparisons with malleable, ductile (nodular), and compacted graphite irons. The mechanical properties of gray iron are determined by the combined effects of its chemical composition, processing technique in the foundry, and cooling rates during solidification. The article provides information on the classification of gray irons based on ASTM International specification A48/A48M. It discusses the loading effect, surface effect, notch sensitivity, and environmental effect on the mechanical properties of gray iron. The chemical composition ranges of some of the more widely used heat-resistant gray irons suitable for elevated-temperature service are presented in a table.

Ductile iron, also known as nodular iron or spheroidal graphite iron, is second to gray iron in the amount of casting produced. This article discusses the common grades of ductile iron that differ primarily by the matrix structure that contains the spherical graphite. The grades of ductile iron designated by their tensile properties in the specification ASTM A536 are presented in a table. The article various reviews factors, such as microstructure, composition, and section effect, affecting the mechanical properties of ductile iron. It discusses the hardness properties, tensile properties, shear and torsional properties, damping capacity, compressive properties, fatigue properties, and fracture toughness of ductile iron. The article concludes with information on the applications of austempered ductile iron.

This article reviews the general mechanical properties and test methods commonly used for ceramics and three categories of polymers, namely, fibers, plastics, and elastomers. The mechanical test methods for determining the tensile strength, yield strength, yield point, and elongation of plastics include the short-term tensile test, the compressive strength test, the flexural strength test, and the heat deflection temperature test. The most commonly used tests for impact performance of plastics are the Izod notched-beam test, the Charpy notched-beam test, and the dart penetration test. Two basic test methods for a group or strand of fibers are the single-filament tension and tow tensile tests. Room temperature strength tests, high-temperature strength tests, and proof tests are used for testing the properties of ceramics.

This article aims to comprehensively review and summarize the material properties and engineering data for aluminum alloy castings and their many applications. The discussion focuses on conventional sand, permanent mold, and die castings as well as the premium engineered versions of some alloys. The article provides a summary of aluminum casting alloy designations of The Aluminum Association, the Unified Numbering System, and specific alloys considered premium strength by definition and by ASTM International and Aerospace Material Specifications. A distillation of data from published industry sources is given for a wide range of the properties and performance characteristics for topics such as: physical and thermophysical properties, typical and minimum mechanical properties, fatigue resistance, fracture resistance, and subcritical crack growth.

This article begins with a description of the classes and grades of ductile iron. It discusses the factors affecting the mechanical properties of ductile iron. The article reviews the hardness properties, tensile properties, shear and torsional properties, compressive properties, fatigue properties, fracture toughness, and physical properties of ductile iron and compares them with other cast irons to aid the designer in materials selection. It concludes with information on austempered ductile iron.

The process of fatigue failure consists of three stages: initial fatigue damage leading to crack initiation; crack propagation to some critical size; and final, sudden fracture of the remaining cross section. Variations in mechanical properties, composition, microstructure, and macrostructure, along with their subsequent effects on fatigue life, have been studied extensively to aid in the appropriate selection of steel to meet specific end-use requirements. The metallurgical variables having the most pronounced effects on the fatigue behavior of carbon and low-alloy steels are strength, ductility, cleanliness, residual stresses, surface conditions, and aggressive environments. The article discusses the stress-based and strain-based approach to fatigue. The application of fatigue data in engineering design is complicated by the characteristic scatter of fatigue data; variations in surface conditions of actual parts; variations in manufacturing processes such as bending, forming, and welding; and the uncertainty of environmental and loading conditions in service.

This article discusses the fatigue and fracture behavior of various types of cast iron, such as gray iron, ductile iron, malleable iron, compacted graphite iron, and white iron, as a function of chemical composition, matrix microstructure, and graphite morphology.

Stress-corrosion cracking (SCC) occurs under service conditions, which can result, often without any prior warning, in catastrophic failure. Hydrogen embrittlement is distinguished from stress-corrosion cracking generally by the interactions of the specimens with applied currents. To determine the susceptibility of alloys to SCC and hydrogen embrittlement, several types of testing are available. This article describes the constant extension testing, constant load testing, constant strain-rate testing for smooth specimens and precracked or notched specimens of SCC. It provides information on the cantilever beam test, wedge-opening load test, contoured double-cantilever beam test, three-point and four-point bend tests, rising step-load test, disk-pressure test, slow strain-rate tensile test, and potentiostatic slow strain-rate tensile test for hydrogen embrittlement.

This article summarizes the general fatigue and fracture properties of cast steels, namely, toughness, fatigue, and component design factors such as section size and discontinuities. It describes the various factors that influence fatigue of cast steels. These factors include section size, defect size, stress modes, and waveform types. The article discusses various fracture mechanics in cast steels: cyclic stress-strain behavior and low- and high-cycle fatigue life behavior; plane-stress fracture toughness; plane-strain fracture toughness; constant-amplitude fatigue crack initiation and growth; and variable-amplitude fatigue crack initiation and growth.

This article briefly introduces some commonly used methods for mechanical testing. It describes the test methods and provides comparative data for the mechanical property tests. In addition, creep testing and dynamic mechanical analyses of viscoelastic plastics are also briefly described. The article discusses the processes involved in the short-term and long-term tensile testing of plastics. Information on the strength/modulus and deflection tests, impact toughness, hardness testing, and fatigue testing of plastics is also provided. The article describes tension testing of elastomers and fibers. It covers two basic methods to test the mechanical properties of fibers, namely the single-filament tension test and the tensile test of a yarn or a group of fibers.