Tuesday, June 5, 2012: 9:00 AM
Cyperus 1 (Hilton Chicago/Indian Lakes Resort)
Dr. Adrian T. DeWald
,
Hill Engineering, LLC, Rancho Cordova, CA
Dr. Daira Legzdina
,
Honeywell Aerospace, Phoenix, AZ
Dr. Bjørn Clausen
,
Los Alamos National Laboratory, Los Alamos, NM
Dr. Donald W. Brown
,
Los Alamos National Laboratory, Los Alamos, NM
Thomas Sisneros
,
Los Alamos National Laboratory, Los Alamos, NM
Prof. Michael R. Hill
,
University of California, Davis, CA
Titanium alloys are widely used in Aerospace applications for their high strength to weight ratio, good corrosion resistance and metallurgical stability. New joining methods are being implemented that allow for more efficient manufacture of titanium components. Linear Friction Welding (LFW) is a solid phase bonding process, which is particularly appropriate for titanium alloys. Due to the titanium’s great affinity for oxygen, nitrogen and hydrogen, protective atmospheres must be used not to contaminate the welded material. LFW avoids the formation of a liquid phase during the welding process, and can therefore be carried out in air. The typical defects caused by melting and solidification during traditional welding process such as pores, pinholes, shrinkage cracks and grain coarsening are therefore avoided. However, as with all welding and deformation processes, understanding the residual stress in the welded component is important.
Results will be presented from recent residual stress measurements on test specimens containing a linear friction weld. The test specimens were 0.5 inch thick plates containing a LFW butt-joint. Residual stress measurements were performed on the test specimens using the contour method and neutron diffraction. The contour method provided 2D maps of residual stress within the welded specimen. A comparison of the data from the two techniques is provided, which is quite favorable. In general, the residual stresses from the LFW process are shown to be high in magnitude and localized near the weld (nominally 5 mm). In addition, thermal stress relieving processes were investigated as a means to reduce the level of residual stress in the welded component. Measurement results from a stress relieved specimen will also be presented.