Accession Number : AD0635249

Title :   HARDENING MECHANISMS IN A COBALT-BASE SUPERALLOY.

Descriptive Note : Master's thesis.

Corporate Author : ARIZONA UNIV TUCSON DEPT OF METALLURGICAL ENGINEERING

Personal Author(s) : Lee, Charles S.

Report Date : 1966

Pagination or Media Count : 147

Abstract : A study was made of the heat treatment response and hardening mechanism of an experimental cobalt-base superalloy, AR-213. Solution treatment temperatures in the range of 1800 to 2250 F and aging temperatures from 1200 to 1900 F were investigated. Selected aged specimens corresponding to the 2200 F solution treatment were intensively studied using optical and electron microscopy and x-ray techniques to determine the hardening mechanism. The results of the study show that a maximum aged hardness of R sub C 47 is obtainable. The hardening mechanism is the precipitation of CoA1 from the supersaturated matrix at temperatures between 1400 and 1600 F. This precipitate overages relatively rapidly at temperatures above 1600 F. A tantalum-zirconium carbonitride was also present in the alloy in a surprisingly large amount. (Author)

Descriptors :   (*COBALT ALLOYS, *HARDENING), HARDNESS, HEAT TREATMENT, AGING(MATERIALS), MICROSTRUCTURE, CHROMIUM ALLOYS, ALUMINUM ALLOYS, TUNGSTEN ALLOYS, TANTALUM ALLOYS, DISPERSION HARDENING, CRYSTAL DEFECTS

Subject Categories : Properties of Metals and Alloys
      Fabrication Metallurgy

Distribution Statement : APPROVED FOR PUBLIC RELEASE