Presentation on theme: "Tungsten Cable Failure Analysis Brad James Ph.D. P.E."— Presentation transcript:
Tungsten Cable Failure Analysis Brad James Ph.D. P.E.
Tungsten Cable Failure Analysis Background Medical device company uses tungsten cables as part of a surgical apparatus Non-sterilized cables withstand hundreds of durability test cycles (consists of cyclic and static loading) Sterilized cables fail after a few durability test cycles Tensile testing shows no real difference between sterilized and non-sterilized cables
Tungsten Cable Failure Analysis Conclusions Classic case of hydrogen embrittlement! (tungsten is known to be susceptible) Corrosion during sterilization is the source of hydrogen Embrittlement is stress/time dependent Tensile testing not long enough to allow diffusion of hydrogen to high stress locations Static loads during durability allowed hydrogen to diffuse to higher stress locations – resulting in fracture