This article reviews the basic equipment and methods for creep and creep rupture testing. It begins with a discussion on the creep properties, including stress and temperature dependence, as well as of the extrapolation techniques that permit estimation of the long-term creep and rupture strengths of materials. The article describes the different types of equipment for determination of creep characteristics, including test stands, furnaces, and extensometers. It also discusses the different testing methods for creep rupture: constant-load testing and constant-stress testing. The article presents other testing considerations and concludes with information on stress relaxation testing.

This article presents effective stress equations that are based on the von Mises criterion, the Tresca criterion, and the Huddleston criterion. It describes the calculation of effective stresses for different cases: elastic stresses, steady-state creep stresses, stresses in a fully plastic case, and thermal stresses in a tube. The article illustrates the comparison of life predictions by the stress criteria and presents a simple mean diameter hoop stress equation, which is used for designing components. It also provides information on the multiaxial creep ductility of tubular components and multiaxial testing methods.

This article presents typical problems encountered in the analysis of experimental creep and creep-rupture data and the possible solutions to these drawbacks. It provides information on planning the test and creep strain/time relationships. The exponential creep equation and the rational polynomial creep equation are discussed. The article also describes the dependence of stress and temperature on equation parameters and explains the lot-centered regression analysis.

This article discusses the methods for assessing creep-rupture properties, particularly, nonclassical creep behavior. The determination of creep-rupture behavior under the conditions of intended service requires extrapolation and/or interpolation of raw data. The article describes the various techniques employed for data handling of most materials and applications of engineering interest. These techniques include graphical methods, methods using time-temperature parameters, and methods used for estimations when data are sparse or hard to obtain. The article reviews the estimation of required creep-rupture properties based on insufficient data. Methods for evaluation of remaining creep-rupture life, including parametric modeling, isostress testing, accelerated creep testing, evaluation by the Monkman-Grant coordinates, and the Materials Properties Council (MPC) Omega method, are also reviewed.

The principal types of elevated-temperature mechanical failure are creep and stress rupture, stress relaxation, low- and high-cycle fatigue, thermal fatigue, tension overload, and combinations of these, as modified by environment. This article briefly reviews the applied aspects of creep-related failures, where the mechanical strength of a material becomes limited by creep rather than by its elastic limit. The majority of information provided is applicable to metallic materials, and only general information regarding creep-related failures of polymeric materials is given. The article also reviews various factors related to creep behavior and associated failures of materials used in high-temperature applications. The complex effects of creep-fatigue interaction, microstructural changes during classical creep, and nondestructive creep damage assessment of metallic materials are also discussed. The article describes the fracture characteristics of stress rupture. Information on various metallurgical instabilities is also provided. The article presents a description of thermal-fatigue cracks, as distinguished from creep-rupture cracks.

This article reviews the applied aspects of creep and stress-rupture failures. It discusses the microstructural changes and bulk mechanical behavior of classical and nonclassical creep behavior. The article provides a description of microstructural changes and damage from creep deformation, including stress-rupture fractures. It also describes metallurgical instabilities, such as aging and carbide reactions, and evaluates the complex effects of creep-fatigue interaction. The article concludes with a discussion on thermal fatigue and creep fatigue failures.

This article focuses on the subject of proactive or predictive maintenance with particular emphasis on the control and prediction of corrosion damage for life extension and failure prevention. It discusses creep life assessment from the perspective of creep-rupture properties and creepcrack growth. Practical methods based on replication and parametric approaches are also discussed.

Understanding the mechanical properties of aluminum alloys is useful for the designer for choosing the best alloy and establishing appropriate allowable stress values, and for the aluminum producer to control the fabrication processes. This article discusses the nature and significance of mechanical property data and of stress-strain curves detailing the effects of mechanical properties on the design and selection of aluminum alloys. The properties include tensile, compressive, shear, bearing, creep and creep-rupture, fatigue, and fracture resistance properties.

Understanding the mechanical properties of aluminum alloys is useful for the designer for choosing the best alloy and establishing appropriate allowable stress values, and for the aluminum producer to control the fabrication processes. This article discusses the nature and significance of mechanical property data and of stress-strain curves detailing the effects of mechanical properties on the design and selection of aluminum alloys. The properties include tensile, compressive, shear, bearing, creep and creep-rupture, fatigue, and fracture resistance properties.

This article reviews the basic mechanisms of elevated-temperature behavior and associated design considerations, with an emphasis on metals. It discusses the key concepts of elevated-temperature design. These include plastic instability at elevated temperatures; deformation mechanisms and strain components associated with creep processes; stress and temperature dependence; fracture at elevated temperatures; and environmental effects. The article describes the basic presentation and analysis methods for creep rupture. It provides information on the application of these methods to materials selection and the setting of basic design rules. The article examines the limitations of high-temperature components as well as the alternative design approaches and tests for most high-temperature components.

The article commences with an overview of short-term and long-term mechanical properties of polymeric materials. It discusses plasticization, solvation, and swelling in rubber products. The article further describes environmental stress cracking and degradation of polymers. It illustrates how surface degradation of a plain strain tension specimen alters the ductile brittle transition in polyethylene creep rupture. The article concludes with information on the effects of temperature on polymer performance.

This datasheet provides information on composition limits, key metallurgy, fabrication characteristics, processing effects on physical, tensile, and creep-rupture properties, and applications of Al-Cu-Mg-Ni alloys 2618 and 2618A. The influence of prolonged holding at elevated temperature on tensile properties and the influence of temperature on compressive yield strength of alloy 2618-T61 hand-forged billets are illustrated.

This article is a comprehensive collection of tables and curves that present data on the properties of aluminum castings. Data are presented to explain the physical properties such as ratings of castability, corrosion resistance, machinablity, and weldability for aluminum casting alloys. The article discusses the typical mechanical properties and mechanical-property limits for aluminum sand casting alloys, permanent mold casting and die casting alloys based on tests of separately cast specimens; and typical mechanical properties of premium-quality aluminum alloy castings and elevated-temperature aluminum casting alloys. It provides a list of the creep-rupture properties and fatigue strengths of separately sand cast test bars of alloy 201.0, alloy C355.0-T61, alloy A356.0-T61, and alloy 354.0-T61.

This article provides the theoretical background for understanding many of the physical processes relevant to mechanical testing methods, experimental results, and analytical approaches described in this volume.

Soft-interlayer solid-state welds that join stronger base metals have unique mechanical properties that are of fundamental interest and may be of critical importance to designers. This article discusses the mechanical properties of soft-interlayer solid-state welds and the implications of these behaviors to service stress states and environments. It describes the tensile loading of soft-Interlayer welds in terms of the effect of interlayer thickness on stress, interlayer strain, time-dependent failure, effect of base-metal properties, and effect of interlayer fabrication method. The article concludes with a discussion on multiaxial loading.

This article discusses the mechanical properties of soft-interlayer solid-state welds and the implications of these behaviors to service stress states and environments. It illustrates the microstructure of as-deposited coatings and solid-state-welded interlayers. The article reviews factors that affect the tensile loading of strength of soft-interlayer welds: the interlayer thickness, the interlayer strain, and the interlayer fabrication method. It also provides information on stress-corrosion cracking of interlayers and stress behavior of these interlayers during shear and multiaxial loading.

Cast nickel-base alloys are used extensively in corrosive-media and high-temperature applications. This article briefly reviews the common types of heat treatments of nickel alloy castings: homogenization, stress relieving, in-process annealing, full annealing, solution annealing, quenching, coating diffusion, and precipitation. It describes the three general strengthening mechanisms, namely, solid-solution hardening, age hardening, and carbide precipitation. The article summarizes the typical heat treatment of the general families of nickel-base castings used in industrial applications. It focuses on the solution treatment and age hardening of cast nickel-base superalloys and the heat treatment of cast solid-solution alloys for corrosion-resisting applications. The article also discusses the typical types of atmospheres used in annealing or solution treating: exothermic, endothermic, dry hydrogen, dry argon, and vacuum.

Stainless steels are widely used at elevated temperatures when carbon and low-alloy steels do not provide adequate corrosion resistance and/or sufficient strength at these temperatures. This article deals with the wrought stainless steels used for high temperature applications. It gives some typical compositions of wrought heat-resistant stainless steels, which are grouped into ferritic, martensitic, austenitic, and precipitation-hardening (PH) grades. Quenched and tempered martensitic stainless steels are essentially martensitic and harden when air cooled from the austenitizing temperature. These alloys offer good combinations of mechanical properties. The article focuses on mechanical property considerations and corrosion resistance considerations of stainless steels. The corrosion and oxidation resistance of wrought stainless steels is similar to that of cast stainless steels with comparable compositions.

This article discusses some elevated-temperature properties of carbon steels and low-alloy steels with ferrite-pearlite and ferrite-bainite microstructures for use in boiler tubes, pressure vessels, and steam turbines. The selection of steels to be used at elevated temperatures generally involves compromise between the higher efficiencies obtained at higher operating temperatures and the cost of equipment, including materials, fabrication, replacement, and downtime costs. The article considers the low-alloy steels which are the creep-resistant steels with 0.5 to 1.0% Mo combined with 0.5 to 9.0% Cr and perhaps other carbide formers. The factors affecting mechanical properties of steels include the nature of strengthening mechanisms, the microstructure, the heat treatment, and the alloy composition. The article describes these factors, with particular emphasis on chromium-molybdenum steels used for elevated-temperature service. Although the mechanical properties establish the allowable design-stress levels, corrosion effects at elevated temperatures often set the maximum allowable service temperature of an alloy. The article also discusses the effects of alloying elements in annealed, normalized and tempered, and quenched and tempered steels.

This article discusses the deformation and viscoelastic characteristics of plastics as polymeric materials, focusing on the test methods used for the evaluation of their mechanical properties, methods available for analytically predicting the deformation response of polymers, and the effect of viscoelasticity on the test methods used. Two common ways of evaluating viscoelasticity of plastics are by means of creep experiments and dynamic mechanical experiments. Graphic or tabular analysis of test data, time-temperature superposition, and empirical correlation methods are commonly employed for analytical prediction of deformation characteristics of polymers.