Metallurgical Investigation of a Ti6242 disk with fatigue progression from sub-surface micro-voids

Ti6242 is a titanium alloy commonly used in the manufacture of static and rotating hardware in aerospace engine applications. This paper will present the results of an investigation into the cracking of a Ti6242 component emanating from an atypical microstructural feature. The observed crack was due to fatigue with an origin at a cluster of subsurface micro-voids containing internal alkaline earth metal deposits. This paper presents the results of this investigation, as well as details of a root cause investigation into possible sources of the micro-voids and deposits.