Copper electrical feedthrough pins used in a bolting application in a refrigeration compressor had functioned without failure for years of production and thousands of units. When some of the pins began to fail, an investigation was conducted to determine the cause. Visual examination revealed that the observed fractures were mixed brittle intergranular with ductile microvoid dimples. An extensive analysis of failed samples combined with a process of elimination indicated that the fractures were due to stress-corrosion cracking caused by an unidentified chemical species within the sealed compressor chamber. A unique combination of applied stress, residual stress, stress riser, and grain size helped isolate the failure mechanism to a single production lot of material.

Diode leads that were to be made from OFHC copper were instead made from copper with high oxygen content. The leads had a nickel underplating, a gold final plating, and were brazed to the diode package in a hydrogen atmosphere. After brazing, the leads became embrittled. SEM examination of the fractured leads revealed voids and some oxidized areas surrounded by ductile fracture areas. High pressure steam pockets observed as voids in the microstructure caused hydrogen embrittlement of the leads. The obvious corrective action was to ensure that the lead material was OFHC copper.