Work strengthening by a deformation-induced phase transformation in “MP alloys”
Tóm tắt
Work strengthening and microstructure were investigated for a class of alloys, designated “MP Alloys”, containing 20 pct Cr, 10 pct Mo, and the remainder cobalt and nickel in proportions ranging from 60Co∶10Ni to 30Co∶40Ni. These alloys, in the fully annealed, homogenized condition, have a fcc structure with yield strengths ranging from about 45 to 60 ksi. Deformation at room temperature rapidly increases the yield strength of the alloys to about 250 ksi. Structural analyses by X-ray and electron diffraction techniques indicate that this marked increase in strength is associated with a deformation-induced martensitic transformation forming a network of extremely thin hcp platelets within the fcc grains. The nature of this martensitic transformation was studied as a function of alloy composition, deformation temperature, and structural variables, such as the platelet size, thec/a ratio of the hcp phase, and twinning.
Tài liệu tham khảo
US Patent No. 3,356,542.
G. D. Smith and D. H. Yates:Metals Progr., 1968, vol. 93, pp. 100–02.
A. C. Hood:Metals Progr., 1968, vol. 93, pp. 81–84.
A. Giamei, J. Burma, and E. J. Freise:Cobalt, 1968, no. 39, pp. 88–96.
F. R. Morral:J. Metals, 1968, vol. 20, pp. 52–59.
R. F. Decker and R. R. DeWitt:J. Metals, 1965, vol. 17, pp. 139–45.
J. L. Youngblood:ASM Trans. Quart., 1969, vol. 62, no. 4.
J. W. Christian:The Theory of Transformations in Metals and Alloys, pp. 808–11, Pergamon Press, New York, 1965.
M. Sage and Ch. Guillaud:Rev. Met., 1950, vol. 47, pp. 139–45.
B. D. Cullity:Elements of X-ray Diffraction, p. 58, Addison-Wesley, Reading, Mass., 1956.
H. S. Rosenbaum:Deformation Twinning, R. E. Reed-Hill, J. P. Hirth and H. C. Rogers, Eds., p. 73, Gordon and Breach Science Publishers, New York, 1964.
B. E. Warren:Progress in Metal Physics, B. Chalmers and R. King, Eds., vol. 8, p. 178, Pergamon Press, New York, 1959.
M. S. Paterson:J. Appl. Phys., 1952, vol. 23, pp. 805–11.