Low Yield Strength in Titanium 6-4

[HeaTreater]

We have some 6-4 Ti parts that were forged and heat treated in a single lot. However, subsequent mechanical testing on them revealed that some parts had depressed Yield strength while maintaining the same Ultimate strength and ductility as the other parts with higher yield strength. What could cause depression in yield strength?

 

[CoryPad]

chemical composition variation and/or segregation

property anisotropy after forming (crystallographic orientation)

temperature variation during any of the processing steps

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[HeaTreater]

Cory,

Thank you for your suggestions. Could not respond sooner as I was out of office.

Thank you!