Alloy having improved fatigue crack growth resistance
AssigneeAluminum Company of America
InventorsPhilip E. Bretz, Jocelyn I. Petit, Ralph R. Sawtell, Asuri K. Vasudevan
Life of this patent
Estimating the term…
Abstract
Disclosed is a metal alloy product having increased resistance to fatigue crack growth and having coarse grains distributed in a fine grain structure, the coarse grains having a different alloy composition from the fine grain structure.
Claims43
A method of increasing the fatigue crack growth resistance of a metal powder product comprising the steps of:
- (a) providing a base metal powder alloy;
- (b) admixing with said base metal alloy powder a second powder to provide a blend, the second powder capable of providing a grain size in said product greater than that resulting from the base metal powder;
- (c) pressing the blend to make a green compact;
- (d) hot pressing the green compact;
- (e) working the hot pressed compact to a shaped product and;
- (f) heat treating the shaped product to provide a final product having coarse grains in a fine grain structure having improved resistance to fatigue crack growth.
A method of increasing the fatigue crack growth resistance of an aluminum alloy product comprising the steps of:
- (a) providing a base aluminum alloy;
- (b) admixing with said base aluminum alloy a second alloy to provide a blend, the second alloy capable of providing a grain size in said product greater than that resulting from the base aluminum alloy;
- (c) pressing the blend to make a green compact:
- (d) hot pressing the green compact;
- (e) working the hot pressed compact to a shaped product and;
- (f) heat treating the shaped product to provide therein coarse grains in a fine grain structure, the product having improved resistance to fatigue crack growth.
A method of increasing the fatigue crack growth resistance of an aluminum alloy powder product comprising the steps of:
- (a) providing a base aluminum alloy powder;
- (b) admixing with said base aluminum alloy powder a second alloy powder to provide a blend, the second powder having a particle size greater than the base powder and capable of providing a grain size in said product greater than that resulting from the base aluminum alloy powder, the blend containing 5 to 50 wt. % of the second powder, and being mixed to produce a substantially uniform distribution of the large particles throughout the base powder;
- (c) pressing the blend to make a green compact;
- (d) hot pressing the green compact;
- (e) hot working the hot pressed compact to a final shaped product, the hot working being performed at a temperature in the range of 550.degree. to 800.degree. F.;
- and
- (f) solution heat treating the final shaped product at a temperature in the range of 800.degree. to 1100.degree. F. and thereafter aging to provide therein coarse grains resulting from the second powder in a fine grain structure, the product having improved resistance to fatigue crack growth.
A metal alloy product having increased resistance to fatigue crack growth and having coarse grains distributed in a fine grain structure, the coarse grains having a different alloy composition from the fine grain structure.
An aluminum base alloy product resulting from two aluminum alloys, the product having increased resistance to fatigue crack growth and having coarse grains distributed in a fine grain structure, the coarse grains developed from one of the aluminum alloys and the fine grain structure developed from the remaining aluminum alloy.
An aluminum base alloy product resulting from a blend of a base aluminum alloy powder and a second aluminum alloy powder, the product having increased resistance to fatigue crack growth and having coarse grains distributed in a fine grain structure, the coarse grains developed from one of the second aluminum alloy powder and the fine grain structure developed from the base aluminum alloy powder.
Dependencies are inferred from the claim text.