BEAR LABS

Failure Analysis Glossary Terms 

• Abrasive Wear (Failure Mechanism) - material removal as a result of another material moving along the surface with a load.  

• Adhesive Wear (Failure Mechanism) - wear and material loss resulting from two materials sliding against each other as a result of localized bonding.

• Anneal (Heat Treating Process) - a process by which a material (usually metal or glass) is allowed to cool slowly to relieve internal stresses.  Rate of cooling affects final material properties.

• Bend Test - a material evaluation test where the force to bend a material in a certain orientation is measured.  

• Brinell Hardness Testing - a technique to evaluate the indentation hardness of a material using a round ball indenter.  This method is best for very coarse materials, or materials with rougher surfaces.  

• Carbonitriding - a surface modificaiton process by which carbon and nitrogen atoms are diffused into the surface of a metal to increase the material's surface hardness.

• Corrosion - a chemical or electrochemical process by which a material is deteriorated as a result of reacting with its environment.  

• Energy Dispersive Spectroscopy (EDS) - a material evaluation method in which materials can be identified based on how they react to electrons.  See our SEM page. 

• Fatigue (Failure Mechanism) -  a process by which a material fails due to repeated and continuous wear. 

• Fracture Toughness - a material property that represents the amount a stress a material can handle before a pre-existing flaw (i.e. crack) propogates (grows).  

• Hydrogen Embrittlement (Failure Mechanism) - or "Hydrogen Assisted Cracking (HAC), a process by which hydrogen atoms are absorbed by a material and leads to embrittlement and failure at a lower tensile strength. 

• Metallography - a material evaluation technique to analyze a metal by evaluating its physical components, such as microstructure, using visual techniques (microscopy). 

• Microstructure - the structure of material at a microscopic level, usually under a microscope at the nm-cm scale.  At this level, you can usually see the grains structure of a metal, or the arrangement of phases and defects of the material.  Miscrostructure can reveal processing and composition history of a metal. 

• Residual Stress - built up stress in a material, whether as a result of heat treatments or other physical events. 

• Rockwell Hardness Test - Another indentation hardness technique, where the indenter is either a conical diamond or a steel ball depending on the scale used. 

• Scanning Electron Microscope (SEM) - a microscope that utilizes electrons to "see" materials at extremely high magnification.  See our SEM page. 

• Tensile Testing - a test method that obtains material property information about a material by pulling on test bar (usually of a standardized size) vertically at a steady rate until failure.  The behavior of the material during the test reveals tensile strength, yield strength, elongation to break, and modulus of a material, along with implications of other properties.