A microstructural and mechanical property correlation of friction stir processed nickel aluminum bronze
Williams, Robert A.
McNelley, Terry R.
MetadataShow full item record
Friction Stir Processing (FSP) is novel technique for localized modification of the surface layer of materials. FSP produces high local strains, strain rates and local temperatures that are 0.8 - 0.9 Tm, where Tm is the melting point. The processing enhances the microstructural and mechanical properties of materials through intense plastic deformation. This thesis examines the microstructure and tensile properties in FSPed Nickel Aluminum Propeller Bronze (NAB) as a function of position in the stir zone using a unique miniature tensile sample design. Test materials were single and multi-pass FSP runs from both 6 mm and 13 mm tools. Tensile ductility was observed to increase from 11 percent to more than 30 percent elongation to fracture at locations along the center of the stir zone. Yield and ultimate strengths also increased two-fold. These improved properties were associated with the formation of WidmanstaÌ tten [a] and fine, equiaxed [a] at peak temperatures of approximately 1000 [degrees] C in these locations. Some locations in the heat affected zone (HAZ) or thermomechanically affected zone (TMAZ) exhibited ductilities below that of as-cast material. Such regions had microstructures that contained a dark-etching constituent formed by cooling after being heated to approximately 800 [degrees] C.
Showing items related by title, author, creator and subject.
Microstructural characterization of TI-44AL-11NB in the chill-cast and directionally solidified configurations Halladay, Timothy R. (Monterey, California. Naval Postgraduate School, 1998-12-01);The microstructural evolution in chill-cast and directionally solidified Ti-44Al-11Nb (at.%) was studied by x-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) methods. ...
Meyers, M.A.; Perez-Prado, M.T.; Xue, Q.; Xu, Y.; McNelley, T.R. (American Institute of Physics, 2001);Shear bands were generated under prescribed and controlled conditions in stainless steel (Fe- 18%Cr-8%Ni). Hat-shaped specimens, deformed in a Hopkinson bar were used, yielding strain rates of approximately 104s-1 and ...
Young, Garth William II (Monterey, California. Naval Postgraduate School, 2012-03);This thesis describes the microstructural and mechanical property changes associated with Friction Stir Processing (FSP) of HY-80 steel under dry and underwater conditions. HY-80 is a low-carbon alloy steel that is used ...