Q:
What is Characterization, and why do it?



A:

Characterization enables quantification of physical properties
important for success of a part used in a given environment.
It assumes that the environment can be defined.
    Mechanical/Physical
  • Stress - tensile, compressive, flexure, etc.
  • Impact, cyclical - including strain rate
  • Phase content, surface morphology
  • Thermal, electrical, etc., as applicable


    Chemical/Corrosive
  • Liquid
  • Gaseous


    Thermal
  • Elevated temperature - accelerates
    chemical reactions, e.g., oxidation
  • Micro structural effects may be present


    Reasons for Characterization

  • In design/development, must qualify a part
    for the predicted environment, then test it in
    prototype systems or carefully designed and
    controlled "real world" use.

  • If conducting a post mortem, the purpose is to
    describe the steps leading to the observed failure
    so future parts can be fixed -- usually through
    surface engineering.

  • Regardless of motive for characterization
    start with the environment of use: temperature,
    stresses - type/magnitude, atmosphere - corrosive/
    oxidative, etc.