Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUSRE29038 E
Publication typeGrant
Application numberUS 05/647,583
Publication dateNov 16, 1976
Filing dateJan 8, 1976
Priority dateMay 8, 1973
Publication number05647583, 647583, US RE29038 E, US RE29038E, US-E-RE29038, USRE29038 E, USRE29038E
InventorsRobert Wayne Balliett
Original AssigneeSt. Joe Minerals Corporation
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
High strength zinc alloys
US RE29038 E
Abstract
Zinc alloys having improved physical properties consist essentially of 10 to 30 percent by weight of aluminum, 0.3 to 10 percent by weight of copper, 0.01 to 0.1 percent by weight of magnesium, 0.005 to 0.3 percent by weight of at least one of the metals calcium, .[.lithium.]. and sodium, and the balance zinc.
Images(2)
Previous page
Next page
Claims(1)
    I claim: .[.1. Zinc base alloys having improved mechanical properties consisting essentially of 20 to 24 percent by weight of aluminum, 0.3 to 10 percent by weight of copper, 0.01 to 0.1 percent by weight of magnesium, 0.005 to 0.3 percent by weight of at least one of the metals
  1. calcium, lithium and sodium, and the balance zinc..]. 2. Zinc base alloys .[.as defined in claim 1.]. .Iadd.having improved mechanical properties .Iaddend.consisting essentially of 20 to 24 percent by weight of aluminum, 0.75 to 1.1 percent .Iadd.by weight .Iaddend.of copper, 0.04 to 0.05 percent by weight of magnesium, 0.01 to 0.03 percent by weight of calcium and balance zinc. .[.3. Zinc base alloys as defined in claim 2 in which the calcium is replaced by lithium..]. .[.4. Zinc base alloys as defined in claim 2 in which the calcium is replaced by sodium..].
Description

It has been known for over twenty-five years that near-eutectoid alloys of zinc and aluminum upon suitable heat treatment acquire the capacity for a high degree of plastic extension which has been termed "superplasticity." A review of the literature in the field of aluminum-zinc superplastic alloys is provided by an article entitled "Superplasticity in an Al-Zn Alloy" by W. A. Backofen et al. in Transactions of the ASM, Vol. 57, 1964, pages 980-990.

U.S. Pat. No. 1,945,288 to Morell disclosed eutectoid alloys of zinc and aluminum containing minor porportions of magnesium and copper. Although the Morrell patent did not explicitly describe the phenomenon of "superplasticity," it became very obvious from the literature in this field cited and discussed in the Backofen article referred to above that the alloys described in the Morell patent possessed the property of superplasticity.

It has now been found that alloys of improved physical properties including high ultimate tensile strengths at ambient temperatures, improved stress rupture lives, and high creep strengths as well as potential superplasticity can be obtained by adding to zinc-aluminum eutectoid alloys containing from 0.3 to 10 percent by weight of copper, and from 0.01 to 0.1 percent by weight of magnesium, small amounts, of the order of from 0.005 to 0.3 percent by weight of at least one of the metals calcium, .[.lithium.]. and sodium. The alloys of the invention contain from 10 to 30 percent by weight of aluminum, the balance being zinc.

For most purposes preferred alloys of the invention contain 20 to 24 percent by weight of aluminum, from about 0.75 to about 1.1 percent by weight of copper, from about 0.04 to about 0.05 percent by weight of magnesium, from about 0.01 to about 0.03 percent by weight of at least one of the metals calcium, .[.lithium.]. and sodium and the balance zinc.

The following are typical alloy compositions of the invention all parts being in percent by weight:

              TABLE I______________________________________No.   Al     Cu     Mg    Ca   Li    Na     Zn______________________________________ 1    22     0.9    0.04  0.02 --    --    Balance .[.2 22     0.9    0.04  --   0.013 --    Balance.]. .[.3 22     0.9    0.04  --   0.032 --    Balance.]..Iadd.2.Iaddend..[.4.]. 22     0.9    0.04  --   --    0.007 Balance.Iadd.3.Iaddend..[.5.]. 22     0.9    0.04  --   --    0.013 Balance______________________________________

The high strength properties of the alloys of the invention can be developed by casting the molten alloy compositions into extrusion billets or rolling slabs. The billets and rolling slabs are then heat-treated between 275 C. and 380 C. to homogenize the material and are water quenched to produce the superplastic structure. The billets or slabs are then reheated to 260 C. and hot-extruded or hot-rolled into rods or sheets. The rods or sheets thus produced are then in condition to be formed into useful products by any of the methods known in the art of forming superplastic alloys.

The practical utilization of the alloys of the invention are not limited to uses involving superplasticity. Other applications of the alloys utilizing their excellent mechanical properties include such metal working techniques as forging (open die, closed die and precision) hot extrusion, impact extrusion, stamping, drawing and screw machine techniques.

The results of tensile strength tests on typical alloys of the invention are given below. In the table the term "hot-worked" denotes the as-rolled or as-extruded material and the term "heat-treated" denotes the material that has been heat-treated between 275 C. and 380 C. and water quenched. The numbered alloys are as in Table I.

              TABLE II______________________________________  Ultimate Tensile Strength (psi)No.      Hot-Worked      Heat-Treated______________________________________ 1       68,000          92,500.[.2     69,000           72,000.]..[.3     70,000           70,000.]..[.4.]..Iadd.2.Iaddend.    60,000          82,000.[.5.]..Iadd.3.Iaddend.    60,000          80,000______________________________________

Comparative ultimate tensile strengths of an alloy consisting of 22 percent by weight of aluminum, 0.9 percent by weight of copper, 0.04 percent by weight of magnesium and balance zinc were 53,000 psi in the hot-worked state and 62,000 psi in the heat-treated state.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1945288 *Jul 9, 1931Jan 30, 1934American Brass CoZinc base alloy
US2102869 *Aug 18, 1937Dec 21, 1937New Jersey Zinc CoZinc alloys
US3527601 *Jun 14, 1967Sep 8, 1970Dow Chemical CoProcess of making creep-resistant zinc-base alloys
US3676115 *Apr 22, 1969Jul 11, 1972Nat Res DevZinc alloys
US3734785 *Nov 30, 1970May 22, 1973Cominco LtdZinc forging alloy
US3741819 *Jan 20, 1971Jun 26, 1973Noranda Metal Ind LtdMethod of preparing low density wrought zinc alloy with improved strength and low temperature ductility
CA899110A *Sep 24, 1968May 2, 1972Noranda Mines LtdLow density wrought zinc alloy with improved strength and low temperature ductility
DE663274C *Jan 27, 1934Aug 2, 1938Metallgesellschaft AgZink-Spritzguss-Legierungen
DE703977C *Feb 14, 1937Mar 20, 1941Metallgesellschaft Ageitung
GB1272117A * Title not available
Classifications
U.S. Classification420/516
International ClassificationC22C18/04
Cooperative ClassificationC22C18/04
European ClassificationC22C18/04
Legal Events
DateCodeEventDescription
Aug 20, 1992ASAssignment
Owner name: MANUFACTURERS HANOVER TRUST COMPANY
Free format text: SECURITY INTEREST;ASSIGNOR:HORSEHEAD INDUSTRIES, INC., A DE CORP.;REEL/FRAME:006238/0001
Effective date: 19911231
Jun 5, 1989ASAssignment
Owner name: CHASE MANHATTAN BANK, N.A., THE
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:HORSEHEAD INDUSTRIES, INC.;REEL/FRAME:005005/0087
Effective date: 19890112
Owner name: MANUFACTURERS HANOVER TRUST COMPANY
Dec 28, 1987ASAssignment
Owner name: NEW JERSEY ZINC COMPANY, 204 EAST 39TH STREET, NEW
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:ST. JOE MINERALS CORPORATION;REEL/FRAME:004843/0464
Effective date: 19870917
Oct 21, 1987ASAssignment
Owner name: MANUFACTURERS HANOVER
Free format text: SECURITY INTEREST;ASSIGNOR:HORSEHEAD INDUSTRIES, INC., A DE CORP.;REEL/FRAME:004818/0173
Effective date: 19870917