Particle size distribution effects in precipitation hardening. [Cu-Co; Ni-Cr-Al; Ni-Al]

Technical Report · Mon Feb 01 04:00:00 EST 1971

OSTI ID:6326171

Ardell, A J

A theoretical modification of the Lifshitz-Slyozov theory of particle coarsening has been developed for the purpose of estimating the effect of volume fraction on the coarsening rates. The modified theory accounts satisfactorily for the literature data on coarsening rates and interfacial free energies in the Cu-Co system. For the modified theory, a calculation of the average center-to-center distance between near-neighbor precipitates is necessary. This problem was also solved to a high level of approximation. Experiments were performed on Ni-Cr-Al and Ni-Al alloys containing high-volume fractions of ..gamma..'. The ..gamma..' coarsening rates in Ni-Cr-Al show the type of volume fraction effect predicted by our theory, but in Ni-Al alloys ..gamma..' coarsens at the same rate, independent of volume fraction over the range 9 to 60%. It is suggested that this is due to the relatively large ..gamma../..gamma..' lattice mismatch in the binary alloy. Progress on other projects in this program is described. Results to date include the completion of a programmable aging furnace and the development of a computer program for matching a specific two-parameter distribution with experimental data obtained from particle size measurements. 13 figures.

• Research Organization: California Univ., Los Angeles (USA). School of Engineering and Applied Science
• DOE Contract Number: AT03-76ER70172
• OSTI ID: 6326171
• Report Number(s): UCLA-34P172-1; ON: DE81027377
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102* -- Metals & Alloys-- Structure & Phase Studies
ALLOYS
ALUMINIUM ALLOYS
CHROMIUM ALLOYS
COBALT ALLOYS
COPPER ALLOYS
HARDENING
KINETICS
NICKEL ALLOYS
PARTICLE SIZE
PRECIPITATION HARDENING
RESEARCH PROGRAMS
SIZE