The isothermal deformation of nickel aluminum bronze in relation to friction stir processing

• Main Author: Pierce, Frank Allen
• Other Authors: McNelley, Terry R.
• Format: Others
• Published: Monterey, California, Naval Postgraduate School June
• Subjects: Aluminum; Friction stir processing; Nickel-aluminum bronze; NAB; Isothermal deformation; Annealing; Optical microscopy; Naval propellers; Surface treatment; Thermomechanically affected zone; Shear deformation; Homogenization of microstructure; Grain refinement
• Online Access: http://hdl.handle.net/10945/1210

Approved for public release, distribution is unlimited === The extreme strain, strain rate and temperature gradients during Friction Stir Processing (FSP) render measurement of key parameters in the stir zone infeasible with common methods. The objective of this research was to separate the effects that temperature and deformation in an experimental study of the microstructure and mechanical properties of Ni-AL bronze (NAB). This was accomplished by subjecting as-cast NAB material to several isothermal annealing and quenching treatments as well as isothermal hot rolling processes. Sufficient material was generated to provide results and data for subsequent optical microscopy, tensile, & hardness tests. All results were then compared to similar data collected from previous works completed here at Naval Postgraduate School and with other DARPA FSP program participants. During the course of this work correlations were drawn between FSP material and the material subjected to isothermal hotworking, which may enhance our understanding of the roles that various FSP process parameters have on the microstructural transformation sequence within this material. The hot-rolling study conducted here suggests that FSP process parameters leading to severe deformation at temperatures between 950-1000 C in the NAB material provides high ductility (elongation approximately 28%) with moderate strengths. === Lieutenant, United States Coast Guard