Patents by Inventor Dhruba Chakrabarti

Dhruba Chakrabarti has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Publication number: 20070000583
    Abstract: Aluminum sheet products having highly anisotropic grain microstructures and highly textured crystallographic microstructures are disclosed. The products exhibit improved strength and improved resistance to fatigue crack growth, as well as other advantageous properties such as improved combinations of strength and fracture toughness. The sheet products are useful for aerospace and other applications, particularly aircraft fuselages.
    Type: Application
    Filed: December 31, 2002
    Publication date: January 4, 2007
    Inventors: Roberto Rioja, Robert Westerlund, Anne Roberts, Dhruba Chakrabarti, Diana Denzer, Anthony Morales, Paul Magnusen, Gregory Venema
  • Publication number: 20060083654
    Abstract: Aluminum alloy products, such as plate, forgings and extrusions, suitable for use in making aerospace structural components like integral wing spars, ribs and webs, comprises about: 6 to 10 wt. % Zn; 1.2 to 1.9 wt. % Mg; 1.2 to 2.2 wt. % Cu, with Mg?(Cu+0.3); and 0.05 to 0.4 wt. % Zr, the balance Al, incidental elements and impurities. Preferably, the alloy contains about 6.9 to 8.5 wt. % Zn; 1.2 to 1.7 wt. % Mg; 1.3 to 2 wt. % Cu. This alloy provides improved combinations of strength and fracture toughness in thick gauges. When artificially aged per the three stage method of preferred embodiments, this alloy also achieves superior SCC performance, including under seacoast conditions.
    Type: Application
    Filed: November 28, 2005
    Publication date: April 20, 2006
    Inventors: Dhruba Chakrabarti, John Liu, Jay Goodman, Gregory Venema, Ralph Sawtell, Cynthia Krist, Robert Westerlund
  • Publication number: 20060076093
    Abstract: The present invention provides a mathematical approach to constructing a model of artificially aging to accurately calculate the value of a property in an aluminum alloy product achieved by aging the alloy. The method includes developing a formula having two independent time and temperature evolving expressions, aging the product to achieve the property by heating the product over an aging period determined by the formula and terminating the heating when the property is achieved according to a mathematical formula. The property is calculated as a function of time and product temperature measured over the aging period. Calculation of the property includes integration of the thermal effects on the product over the entire aging period.
    Type: Application
    Filed: November 30, 2005
    Publication date: April 13, 2006
    Inventors: William Bennon, Vivek Sample, Dhruba Chakrabarti
  • Publication number: 20060000094
    Abstract: A method of making a forged aluminum vehicle wheel includes forging a low copper bearing 7000 series aluminum alloy into a wheel workpiece followed by initial cooling and machining and surface treatment. Aging which may be natural aging, artificial aging or both may be provided after cooling and before or after machining. Corresponding forged aluminum wheels are disclosed. The low copper bearing 7000 series forged aluminum wheel has superior fatigue properties. An alloy suitable for use in the method and wheel is disclosed.
    Type: Application
    Filed: May 26, 2005
    Publication date: January 5, 2006
    Inventors: Carl Garesché, Dhruba Chakrabarti, Gregory Nowoslawski, Robert Fecke, Matthew Brest
  • Publication number: 20050269000
    Abstract: This invention relates to a method for artificially aging 7000 Series Al aerospace alloys to impart improved strength and/or corrosion resistance performance thereto. The method purposefully adds a second aging step or stage to a one-step tempering, or a third step/stage to a low-high, two-step aging operation. The added step/stage extends at about 225-275° F. for about 3-24 hours. More preferably, the added stage extends at about 250° F. for about 6 hours or more.
    Type: Application
    Filed: December 3, 2004
    Publication date: December 8, 2005
    Inventors: Diana Denzer, Dhruba Chakrabarti, John Liu, Lynn Oswald, Robert Westerlund
  • Publication number: 20050257865
    Abstract: Aluminum alloy products, such as plate, forgings and extrusions, suitable for use in making aerospace structural components like integral wing spars, ribs and webs, comprises about: 6 to 10 wt. % Zn; 1.2 to 1.9 wt. % Mg; 1.2 to 2.2 wt. % Cu, with Mg?(Cu+0.3); and 0.05 to 0.4 wt. % Zr, the balance Al, incidental elements and impurities. Preferably, the alloy contains about 6.9 to 8.5 wt. % Zn; 1.2 to 1.7 wt. % Mg; 1.3 to 2 wt. % Cu. This alloy provides improved combinations of strength and fracture toughness in thick gauges. When artificially aged per the three stage method of preferred embodiments, this alloy also achieves superior SCC performance, including under seacoast conditions.
    Type: Application
    Filed: February 7, 2005
    Publication date: November 24, 2005
    Inventors: Dhruba Chakrabarti, John Liu, Jay Goodman, Gregory Venema, Ralph Sawtell, Cynthia Krist, Robert Westerlund
  • Publication number: 20050150579
    Abstract: Aluminum alloy products, such as plate, forgings and extrusions, suitable for use in making aerospace structural components like integral wing spars, ribs and webs, comprises about: 6 to 10 wt. % Zn; 1.2 to 1.9 wt. % Mg; 1.2 to 2.2 wt. % Cu, with Mg?(Cu+0.3); and 0.05 to 0.4 wt. % Zr, the balance Al, incidental elements and impurities. Preferably, the alloy contains about 6.9 to 8.5 wt. % Zn; 1.2 to 1.7 wt. % Mg; 1.3 to 2 wt. % Cu. This alloy provides improved combinations of strength and fracture toughness in thick gauges. When artificially aged per the three stage method of preferred embodiments, this alloy also achieves superior SCC performance, including under seacoast conditions.
    Type: Application
    Filed: March 7, 2005
    Publication date: July 14, 2005
    Inventors: Dhruba Chakrabarti, John Liu, Jay Goodman, Gregory Venema, Ralph Sawtell, Cynthia Krist, Robert Westerlund