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FATIGUE PROPERTIES OF HIGH STRENGTH ALUMINIUM TRANSITION METAL BASE ALLOYS PRODUCED BY RAPID SOLIDIFICATION PROCESSIN

Objective

To accelerate the commercial exploitation within Europe of rapidly solidified (RS) aluminium alloys for elevated temperature fatigue applications by: Predicting and assessing the use of alloying additions to enhance fatigue performance through dynamic strain ageing (DSA). Optimizing the alloy processing (both RS feedstock production and consolidation by thermomechanical processing) with respect to fatigue properties.
This research has accelerated the commercial exploitation within Europe of rapidly solidified (RS) aluminium alloys for elevated temperature fatigue applications by predicting and assessing the use of alloying additions to enhance fatigue performance through dynamic strain ageing (DSA), by optimising the alloy processing (both RS feedstock production and consolidation by thermomechanical processing) with respect to fatigue properties and by understanding the physical metallurgical basis for the response of these materials to dynamic forces (fatigue).
Alloying element additions to promote DSA have been predicted. Batches of candidate alloys have been produced by melt spinning to optimise ribbon quality. Kinetics of microstructural degradation of ribbon during processing after RS have been determined. Extrusion conditions have been identified to give full consolidation of flake feedstock and to minimise microstructural degradation. Degassing requirements have been investigated in situ by X-ray photoelectron spectroscopy and in bulk. Mechanical properties have been determined for 2618 and 2 RS alloys provided by sponsors, as well as for extrudes of a range of new alloys. The most promising new compositions have shown evidence of DSA (Sharp fatigue limit). Metallurgical studies have identified deformation mechanisms during deformation of RS materials.
THE RAPID SOLIDIFICATION TECHNIQUE IS A GOOD WAY TO IMPROVE CONVENTIONAL HIGH STRENGHT AL ALLOYS WITH A HIGH RATIO OF MONOTONIC STRENGHT/WEIGHT.

AIMS OF THE PROJECT:

- CLARIFY THE EFFECT OF DIFFERENT MICROSTRUCTURES.
- OPTIMISE THE EFFECT OF ALLOYING.
- INVESTIGATE THE EFFECT OF VARIOUS PRODUCTION PARAMETERS ON FATIGUE STRENGHT.
- GAIN FUNDAMENTAL UNDERSTANDING OF THE RESPONSE OF RS-AL TO DYNAMIC EXTERNAL FORCES.
- PROVIDE GUIDELINES FOR INDUSTRIAL PRODUCTION.
- PROVIDE DESIGN DATA OF RS-AL.

THE FATIGUE PROPERTIES WILL BE COMPARED WITH PROPERTIES OF CONVENTIONAL ALLOYS USED AT ELEVATED TEMPERATURES (AA 2618) AND FIBRE REINFORCED AL-ALLOYS.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

AEA Technology plc
Address
Harwell Laboratory
OX11 0RA Didcot
United Kingdom

Participants (3)

RISO NATIONAL LABORATORY
Denmark
Address
Frederiksborgvej 399
SINTEF
Norway
Tampere University of Technology
Finland
Address

Tampere