Failure Analysis

The term "failure" can refer to a failed part or component or it can refer to an assembly that no longer performs properly. The engineers at Express Testing have extensive experience in evaluating both types of failures.

The failure analysis begins with a thorough documentation of the part or assembly being evaluated. This is done visually and with the aid of stereo microscopes. Photographic documentation of the condition of the samples in the as-received condition is critical prior to any disassembly or destructive evaluation.

After the initial evaluation and the development of an analysis plan, the samples can be examined further using a variety of analysis techniques:

Chemical analysis - the evaluation of a sample to determine if the composition of the part meets the design specifications and to see if any potentially problematic constituents are present.

Scanning Electron Microscopy (SEM) - facilitates the evaluation of fracture surfaces and other important features at extremely high magnification. SEM photographic documentation is also performed to record physical features that indicate a specific failure mode. Material defects can be identified and in the case of an unwanted inclusion it can be chemically analyzed while in the SEM using Energy Dispersive Spectroscopy (EDS) to determine it's potential origin.

Hardness/Microhardness measurement - can vary from routine checks via Rockwell and Brinell hardness to the documentation of small microstructural features and metallurgical cases using microhardness measurement.

Metallographic Examination - Cross-sections can be excised from areas of interest in the sample being evaluated and the microstructure can be examined at high magnification using a metallograph. Specifically, the microscructure at the fracture location can be evaluated to determine if there were specific microstructural defects or anomolies that contributed to fracture initiation or propagation - these defects or areas of interest can be documented photograpically.

Non-destructive Testing - sometimes used when destructive evaluation is not an option or prior to any destructive testing to document crack locations and to sort parts by the worst-case crack if multiple parts are suspect and time or cost prevents the evaluation of numerous samples.

All of the information and data collected during the failure analysis is reviewed and documented in a formal report which includes information related to the failure mode, condition of the material in question and recommendations regarding future avoidance of failures (if applicable).