Fracture behaviour of diffusion bonded bimaterial Ti-Al joints

Gorel Cam, Mustafa Kocak, Daniel Dobi, Liisa Heikinheimo, Mika Siren

Research output: Contribution to journalArticleScientificpeer-review

14 Citations (Scopus)

Abstract

Failure modes of constrained metal foils between two elastic solids are rather different from those in the unconstrained condition. If the interface adhesion is strong between materials, a lower strength thin metal (plastic) foil between two much higher strength metals (elastic) can undergo substantial plastic deformation and fail with high triaxiality induced ductile fracture. Experiments have been conducted to explore the modes of failure and the factors governing fracture in such a constrained metal interlayer. In the present work, the effects of soft inter layer thickness and brittle reaction layer on the fracture behaviour of four point bend specimens have been investigated. A series of solid state diffusion bonds were produced between 25 × 25 mm section titanium bars using pure aluminium foils of different thickness (50, 457, 914, and 2000 μm) as the soft constrained inter layer. All four point bend specimens containing an ∼ 2 μm thick intermetallic reaction layer TiAl3 between the titanium and aluminium failed in ductile fracture mode within the soft aluminium interlayer next to the interface. A number of void formations were observed ahead of the crack tip next to the interface. No evidence of interface debonding was observed. However, the specimens containing an 8 μm thick TiAl3 layer failed by brittle fracture along the interface between the titanium substrate and the TiAl3 layer. It was found that decreasing the soft interlayer thickness from 2000 to 457 μm increased the load carrying capacity and decreased the fracture toughness caused by constrained plastic deformation (high triaxiality) of the interlayer.

Original languageEnglish
Pages (from-to)95 - 101
Number of pages7
JournalScience and Technology of Welding and Joining
Volume2
Issue number3
DOIs
Publication statusPublished - 1997
MoE publication typeA1 Journal article-refereed

Fingerprint

Titanium
Ductile fracture
Metals
Aluminum
Metal foil
interlayers
Plastic deformation
triaxial stresses
Aluminum foil
titanium
Debonding
Brittle fracture
Load limits
aluminum
Crack tips
Failure modes
plastic deformation
Intermetallics
Fracture toughness
foils

Cite this

Cam, Gorel ; Kocak, Mustafa ; Dobi, Daniel ; Heikinheimo, Liisa ; Siren, Mika. / Fracture behaviour of diffusion bonded bimaterial Ti-Al joints. In: Science and Technology of Welding and Joining. 1997 ; Vol. 2, No. 3. pp. 95 - 101.
@article{b8a92449ad714a098c38cc0382cdb970,
title = "Fracture behaviour of diffusion bonded bimaterial Ti-Al joints",
abstract = "Failure modes of constrained metal foils between two elastic solids are rather different from those in the unconstrained condition. If the interface adhesion is strong between materials, a lower strength thin metal (plastic) foil between two much higher strength metals (elastic) can undergo substantial plastic deformation and fail with high triaxiality induced ductile fracture. Experiments have been conducted to explore the modes of failure and the factors governing fracture in such a constrained metal interlayer. In the present work, the effects of soft inter layer thickness and brittle reaction layer on the fracture behaviour of four point bend specimens have been investigated. A series of solid state diffusion bonds were produced between 25 × 25 mm section titanium bars using pure aluminium foils of different thickness (50, 457, 914, and 2000 μm) as the soft constrained inter layer. All four point bend specimens containing an ∼ 2 μm thick intermetallic reaction layer TiAl3 between the titanium and aluminium failed in ductile fracture mode within the soft aluminium interlayer next to the interface. A number of void formations were observed ahead of the crack tip next to the interface. No evidence of interface debonding was observed. However, the specimens containing an 8 μm thick TiAl3 layer failed by brittle fracture along the interface between the titanium substrate and the TiAl3 layer. It was found that decreasing the soft interlayer thickness from 2000 to 457 μm increased the load carrying capacity and decreased the fracture toughness caused by constrained plastic deformation (high triaxiality) of the interlayer.",
author = "Gorel Cam and Mustafa Kocak and Daniel Dobi and Liisa Heikinheimo and Mika Siren",
note = "Project code: V7SU00398",
year = "1997",
doi = "10.1179/stw.1997.2.3.95",
language = "English",
volume = "2",
pages = "95 -- 101",
journal = "Science and Technology of Welding and Joining",
issn = "1362-1718",
publisher = "Maney Publishing",
number = "3",

}

Fracture behaviour of diffusion bonded bimaterial Ti-Al joints. / Cam, Gorel; Kocak, Mustafa; Dobi, Daniel; Heikinheimo, Liisa; Siren, Mika.

In: Science and Technology of Welding and Joining, Vol. 2, No. 3, 1997, p. 95 - 101.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Fracture behaviour of diffusion bonded bimaterial Ti-Al joints

AU - Cam, Gorel

AU - Kocak, Mustafa

AU - Dobi, Daniel

AU - Heikinheimo, Liisa

AU - Siren, Mika

N1 - Project code: V7SU00398

PY - 1997

Y1 - 1997

N2 - Failure modes of constrained metal foils between two elastic solids are rather different from those in the unconstrained condition. If the interface adhesion is strong between materials, a lower strength thin metal (plastic) foil between two much higher strength metals (elastic) can undergo substantial plastic deformation and fail with high triaxiality induced ductile fracture. Experiments have been conducted to explore the modes of failure and the factors governing fracture in such a constrained metal interlayer. In the present work, the effects of soft inter layer thickness and brittle reaction layer on the fracture behaviour of four point bend specimens have been investigated. A series of solid state diffusion bonds were produced between 25 × 25 mm section titanium bars using pure aluminium foils of different thickness (50, 457, 914, and 2000 μm) as the soft constrained inter layer. All four point bend specimens containing an ∼ 2 μm thick intermetallic reaction layer TiAl3 between the titanium and aluminium failed in ductile fracture mode within the soft aluminium interlayer next to the interface. A number of void formations were observed ahead of the crack tip next to the interface. No evidence of interface debonding was observed. However, the specimens containing an 8 μm thick TiAl3 layer failed by brittle fracture along the interface between the titanium substrate and the TiAl3 layer. It was found that decreasing the soft interlayer thickness from 2000 to 457 μm increased the load carrying capacity and decreased the fracture toughness caused by constrained plastic deformation (high triaxiality) of the interlayer.

AB - Failure modes of constrained metal foils between two elastic solids are rather different from those in the unconstrained condition. If the interface adhesion is strong between materials, a lower strength thin metal (plastic) foil between two much higher strength metals (elastic) can undergo substantial plastic deformation and fail with high triaxiality induced ductile fracture. Experiments have been conducted to explore the modes of failure and the factors governing fracture in such a constrained metal interlayer. In the present work, the effects of soft inter layer thickness and brittle reaction layer on the fracture behaviour of four point bend specimens have been investigated. A series of solid state diffusion bonds were produced between 25 × 25 mm section titanium bars using pure aluminium foils of different thickness (50, 457, 914, and 2000 μm) as the soft constrained inter layer. All four point bend specimens containing an ∼ 2 μm thick intermetallic reaction layer TiAl3 between the titanium and aluminium failed in ductile fracture mode within the soft aluminium interlayer next to the interface. A number of void formations were observed ahead of the crack tip next to the interface. No evidence of interface debonding was observed. However, the specimens containing an 8 μm thick TiAl3 layer failed by brittle fracture along the interface between the titanium substrate and the TiAl3 layer. It was found that decreasing the soft interlayer thickness from 2000 to 457 μm increased the load carrying capacity and decreased the fracture toughness caused by constrained plastic deformation (high triaxiality) of the interlayer.

U2 - 10.1179/stw.1997.2.3.95

DO - 10.1179/stw.1997.2.3.95

M3 - Article

VL - 2

SP - 95

EP - 101

JO - Science and Technology of Welding and Joining

JF - Science and Technology of Welding and Joining

SN - 1362-1718

IS - 3

ER -