Accession Number : ADD012629

Title :   Optimizing Hot Workability and Controlling Microstructures in Difficult to Process High Strength and High Temperature Materials.

Descriptive Note : Patent,

Corporate Author : DEPARTMENT OF THE AIR FORCE WASHINGTON DC

Personal Author(s) : Gegel,Harold L ; Malas,James C ; Prasad,Yellapregada V ; Doraivelu,Sokka M ; Barker,Douglas R

Report Date : 21 Oct 1986

Pagination or Media Count : 30

Abstract : An improved hot forming method for metals, alloys and the like, and in particular, for difficult to process high strength and high temperature metals and alloys of particular use in aerospace applications, is described, which comprises the steps of generating flow stress data as a function of strain rate and temperature on samples of the material at predetermined strain within predetermined ranges of temperature and strain rate; determining from that data the strain rate sensitivity and power dissipation efficiency of the material within the ranges of temperature and strain rate represented by the generated data; selecting values of strain rate and corresponding temperature for a selected value of the dissipation efficiency for the material; and hot forming the material at the selected strain rate and temperature values to a predetermined shape. The improved method may be of particular application to forging, extrusion, rolling or other hot forming process appropriate for titanium, aluminum, nickel, cobalt, copper, iron, zirconium and their alloys. A processing map for hot forming each metal or alloy may be generated according to the methods taught.

Descriptors :   *MICROSTRUCTURE, *HOT WORKING, *METALS, *HIGH STRENGTH ALLOYS, AEROSPACE SYSTEMS, ALUMINUM, COBALT, DISSIPATION, EFFICIENCY, FLOW, STRESSES, HIGH TEMPERATURE, ALLOYS, FORGING, COPPER, EXTRUSION, HIGH STRENGTH, NICKEL, SENSITIVITY, STRAIN RATE, TITANIUM, ZIRCONIUM, IRON, POWER

Subject Categories : Properties of Metals and Alloys

Distribution Statement : APPROVED FOR PUBLIC RELEASE