ISSN: 1945-7553
CODEN: JTEVAB
Page Count: 6

The Effect of Very Short Time-at-Temperature on the Yield Stress of 6061-T651 Aluminum

Babcock, SG
Manufacturing Development, General Motors Technical Center, Warren, Mich.

Norvey, DB
Manufacturing Development, General Motors Technical Center, Warren, Mich.

Green, SJ
Terra-Tek, Inc., Salt Lake City, Utah

Holt, DL
School of Engineering, University of Auckland, Auckland,

Abstract

This paper describes the experimental methods and the results of an investigation of the effect of short time-at-temperature (achieved by using high heating rates) on the yield stress of 6061-T651 aluminum in uniaxial tension. Specimens were heated to 260°C at rates from about 10⁻³ to 10³°C/s and then immediately pulled to failure at a constant strain rate of about 10/s. These heating rates, which correspond to approximate times-at-temperature in the range of 10⁻¹ to 10⁵ s, produce a large change in yield stress between times-at-temperature of 10² to 10⁵ s. This change is explained in terms of precipitate coarsening and is substantiated by metallographic evidence. Extrapolation to times-at-temperature in the order of 10⁻⁵ s is discussed, and it is suggested that at these rates changes in yield stress would be due to strain rate effects only.

Keywords:
aluminum, strain rate, heating rate, mechanical testing

Paper ID: JTE10030J
DOI: 10.1520/JTE10030J
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