Accession Number:

ADA503829

Title:

Rheological Behavior of Pure Binary Ni-Nb Model Alloys (Preprint)

Descriptive Note:

Conference paper preprint

Corporate Author:

AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH METALS BRANCH

Report Date:

2009-05-01

Pagination or Media Count:

8.0

Abstract:

This experimental work deals with the influence of niobium additions to high purity nickel on dynamic recrystallization behavior during hot working. Various high-purity alloys were prepared unalloyed Ni and Ni-0.01, 0.1, 1 and 10 wt Nb and deformed to high strains by hot torsion tests to characterize the rheological behavior within the range 800-1000 deg C at strain rates of 0.03, 0.1 and 0.3 s-1. Niobium additions strongly increased the flow stress. To quantify such behavior, the strain-hardening parameter h and dynamic-recovery parameter r in the Yoshie-Laasraoui-Jonas constitutive equation were determined from the initial part of the experimental stress-strain curves i.e., at strains before the stress peak in which dynamic recrystallization does not alter the mechanical behavior. A table showing the variation of h and r as a function of strain rate, temperature, and niobium content was compiled and used to fit qa simple empirical model for predicting h and r from the deformation conditions and alloy composition. In addition, microstructures were determined by optical metallography and SEMEBSD.

Subject Categories:

  • Properties of Metals and Alloys
  • Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE