An electron microscopy study of tweed microstructures and premartensitic effects in high damping 53Cu45Mn2A1 alloy
Mayes, Larry Leroy
Perkins, A.J. (Jeff)
MetadataShow full item record
The evolution of tweed microstructure upon aging a 53Cu45Mn2Al alloy was studied in the transmission electron microscope (TEM). Characteristic (110) tweed contrast develops after the alloy is aged for 4 hours or longer at 400 C, which apparently is just within the miscibility gap, and is then cooled to room temperature. The microstructure evolved is proposed to consist of a small proportion of Mn-rich regions in a Cu-rich matrix. As the phase separation proceeds, the Neel temperature and the FCC-to-FCT transition temperature both rise within these Mn-rich domains, and as a result they begin to display incipient lattice instabilities when observed at room temperature. This takes the form of a 'flickering' effect in the TEM image. The flickering consists of consistent and repetitive contrast variations at specific locations in the microstructure. The significance of these microstructural features to damping is discussed.
Approved for public release; distribution is unlimited
Showing items related by title, author, creator and subject.
The effects of isothermal deformation and annealing on the microstructure of nickel-aluminum-bronze in relation to the friction stir process Vazquez, Brian K. (Monterey, California. Naval Postgraduate School, 2003-12);The FSP of Nickel Aluminum Bronze is a novel approach to enhance the microstructural properties of the material through a shear deformation process. This thesis examines the effect on microstructure of isothermal annealing ...
An examination of microthermal structure statistics as calculated from expendable bathythermograph records. Hunt, Frank Martin Jr. (Monterey, California. Naval Postgraduate School, 1971-09);Expendable Bathythermograph (XBT) temperature depth profile data from 17 locations in the north Pacific Ocean has been analyzed to extract information concerning the thermal microstructure. The microstructure information ...
INVESTIGATING THE CHARACTERISTICS OF THE SOUTHERN BEAUFORT SEA USING ACOUSTICAL OCEANOGRAPHY SENSORS DURING ICEX-18 Collins, Jeffrey D. II (Monterey, CA; Naval Postgraduate School, 2019-03);During Ice Exercise (ICEX) 2018, a 120-kHz echosounder was used to investigate the ocean environment underneath the Arctic ice sheet in the southern Beaufort Sea down to a depth of 200 meters. Returns from the echosounder, ...