This article provides an overview of the classification of hydrogen damage. Some specific types of the damage are hydrogen embrittlement, hydrogen-induced blistering, cracking from precipitation of internal hydrogen, hydrogen attack, and cracking from hydride formation. The article focuses on the types of hydrogen embrittlement that occur in all the major commercial metal and alloy systems, including stainless steels, nickel-base alloys, aluminum and aluminum alloys, titanium and titanium alloys, copper and copper alloys, and transition and refractory metals. The specific types of hydrogen embrittlement discussed include internal reversible hydrogen embrittlement, hydrogen environment embrittlement, and hydrogen reaction embrittlement. The article describes preservice and early-service fractures of commodity-grade steel components suspected of hydrogen embrittlement. Some prevention strategies for design and manufacturing problem-induced hydrogen embrittlement are also reviewed.

This article begins with a discussion on the classification of hydrogen embrittlement and likely sources of hydrogen and stress. The article describes several hydrogen embrittlement test methods, including cantilever beam tests, wedge-opening load tests, contoured double-cantilever beam tests, rising step-load tests, and slow strain rate tensile tests. It also describes the interpretation of test results and how to control hydrogen embrittlement during production.

Hydrogen damage is a term used to designate a number of processes in metals by which the load-carrying capacity of the metal is reduced due to the presence of hydrogen. This article introduces the general forms of hydrogen damage and provides an overview of the different types of hydrogen damage in all the major commercial alloy systems. It covers the broader topic of hydrogen damage, which can be quite complex and technical in nature. The article focuses on failure analysis where hydrogen embrittlement of a steel component is suspected. It provides practical advice for the failure analysis practitioner or for someone who is contemplating procurement of a cost-effective failure analysis of commodity-grade components suspected of hydrogen embrittlement. Some prevention strategies for design and manufacturing problem-induced hydrogen embrittlement are also provided.

Hydrogen damage is a form of environmentally assisted failure that results from the combined action of hydrogen and residual or applied tensile stress. This article classifies the various forms of hydrogen damage and summarizes the theories that seek to explain these types of degradation. It reviews hydrogen degradation in specific ferrous and nonferrous alloys, namely, iron-base alloys, nickel alloys, aluminum alloys, copper alloys, titanium alloys, zirconium alloys, and vanadium, niobium, tantalum, and their alloys. An outline of hydrogen damage in intermetallic compounds is also provided.

This article describes the types, mechanism, and typical test methods along with their configurations for the evaluation of hydrogen embrittlement, stress-corrosion cracking, and corrosion fatigue with an emphasis on fracture mechanics methodologies for metals. An overview on the environmentally assisted crack growth of polymers is also included. The article details the evaluation of nanoscale environmental effects and indentation-induced cohesive cracking. It also provides information on scanning probe microscopy.

This article is a comprehensive collection of terms related to corrosion fundamentals, testing, and protection.

This article focuses on the fractography of Nitinol, a shape memory alloy of nickel and titanium, in superelastic biomedical applications, which primarily comprise drawn and/or laser-cut wire and tube components. Overload fracture, hydrogen embrittlement fracture, and fatigue fracture are discussed in detail.

In this article, a basic summary of fracture mechanisms in carbon and alloy steels is presented, along with numerous examples of these fractures. These examples include ductile fracture, brittle cleavage fracture, intergranular fracture, fatigue fracture, and environmentally assisted failure mechanisms.

Identification of the fracture mechanism is one of the principal responsibilities of a failure analyst and is an important component of any root-cause analysis. This article explores the varied mechanisms responsible for metal fracture, particularly regarding fractography. The behavior of engineering materials at fracture is based on a large number of interrelated characteristics from the atomic level to the component level. These characteristics range from ductile to brittle at the microscale and macroscale levels. Fundamental relative ductility results from the type of electronic bonding, the crystal structure, and the broader long-range degree of order. It provides detailed discussion on ductile fracture, brittle fracture, mixed fracture, embrittlement, stress-corrosion cracking.

This article discusses the basic approach for predicting the corrosion-fatigue life of structural components. It describes two types of tests that are normally used in combination: cycles-to-failure tests, which focus on crack initiation, and crack propagation tests, which focus on crack growth rates under cyclic load. The article examines corrosion-fatigue cracking along with the effects of cracking due to stress corrosion and hydrogen embrittlement, which often occur together. It explains how test parameters such as loading and environmental conditions impact crack growth mechanisms and data interpretation.

This article examines the embrittlement of iron and carbon steels. It describes compositional, processing, and service conditions that contribute to the problem and presents examples of how embrittlement influences mechanical properties. Embrittlement due to hydrogen is the most common form of embrittlement and influences the behavior and properties of nearly all ferrous alloys and many metals. The article explains why hydrogen embrittlement is so widespread and reviews the many types of damage it can cause. It also explores other forms of embrittlement, including metal-induced embrittlement, strain-age and aluminum nitride embrittlement, thermal embrittlement, quench cracking, 475 deg C and sigma phase embrittlement (in FeCr alloys), temper embrittlement, and embrittlement caused by neutron irradiation. In addition, the article covers stress-corrosion cracking along with properties and conditions that affect it, and the procedures to detect and evaluate it.

Many metal failures involve fracture, and fractography is an essential activity in many, if not most, failure analysis (FA) investigations. This article introduces and illustrates the role of fractography in an FA investigation. Basic guidelines are briefly presented for investigating a failure and how fractography helps the FA investigator determine evidence. Examples are given throughout this article on how the examination of fracture surfaces discerns various sources of crack initiation and mechanisms of crack growth. The procedures for analyzing fractures also include several steps and techniques that involve photographic documentation, proper specimen handling, and visual or microscopic examination. The article also briefly describes the use of metallography in fracture analysis along with case studies as illustrative examples of various fracture mechanisms and modes.

Stainless steel alloys have many unique failure mechanisms, including environmentally assisted cracking, cracking associated with welding, and secondary phase embrittlement. This article describes these failure mechanisms and the fracture modes associated with the different categories of stainless steel. These mechanisms and modes are grouped together because of their similarities across the categories.

This article describes the general factors that can influence fracture appearances. The focus is on the general practical relationships of fracture appearances, with factors presented in some broad categories, including: material conditions (e.g., crystal structure and microstructure); loading conditions (stress state, strain rate, and fatigue); manufacturing conditions (casting, metal-working, machining, heat treatment, etc.); and service and environmental factors (hydrogen embrittlement, stress corrosion, temperature, and corrosion fatigue).