Alpha Case Evaluation

Alpha case forms on the surface of titanium alloys due to oxygen or chemical exposures during thermal processing. The alpha case is a hard and brittle surface structure which tends to create a series of microcracks that affects the performance and fatigue properties of the component. Alpha case may be minimized or prevented by heat treating at very deep vacuum level. If alpha case occurs on the surface of metal, most often it is simply removed by either machine milling or by chemical-milling. Removal of alpha-case can cause a second problem; that of maintaining proper part thickness. An alpha case evaluation will show you how much metal must be removed.

It is difficult and complicated to measure and evaluate the formation of alpha case. This is particularly true when the requirement lists that no alpha case is allowed. STEMart offers detailed metallurgical services to accurately assess, characterize and measure the thickness of alpha case on titanium components.

Test Capabilities

• Proper sectioning and sampling of the component to preserve the existing surface condition
• Measurement of the alpha case depth with optical or scanning electron microscope examination to determine if the components meet any of the applicable standard requirements.

For more information about our alpha case evaluation service, please contact us.