SEDL / STP / STP590-EB / STP33948S

Effect of Specimen Size on Fracture Toughness of a Titanium Alloy

Munz, D
DFVLR, Institut für Werkstoff-Forschung, Linder Höhe,

Galda, KH
DFVLR, Institut für Werkstoff-Forschung, Linder Höhe,

Link, F
DFVLR, Institut für Werkstoff-Forschung, Linder Höhe,

Pages: 16    Published: Jan 1976

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Abstract

This paper describes the effect of specimen size on slow crack growth and fracture toughness of the titanium alloy Ti-6A1-4V. The load versus crack opening displacement curve rises steeply after reaching the end of the linear part. Stable crack extension starts within the linear part of the P-v-curve. The crack growth resistance curve is independent of thickness B until KQ in the range 2 < B < 20 mm, leading to the conclusion that slow crack growth can occur in plane strain.

The secant method, leading to KQ at 2 percent crack extension, yields a specimen geometry dependent fracture toughness. KQ increases with width, W and is only slightly dependent on thickness, B.

The consequences of this behavior for fracture toughness determination in connection with the ASTM recommendation are discussed.