Functionally Graded Materials Through Wire Arc Additive Manufacturing


Innovative design of products demands the ability to tailor the microstructure to the property requirements at specific locations in a product. Wire and arc based additive manufacturing processes are novel technologies to create complex large scale 3D-structures that enable functional and compositional grading by selection of appropriate process conditions or by means of multiple wire feed techniques.
In order to be able to create this local difference of properties, the relationships between Wire Arc Additive Manufacturing (WAAM) process conditions, the thermal history during the building process and the resulting microstructure (i.e. the properties) of the materials considered, needs to be fully understood.
The approach followed in this project starts with the determination of a processing window were process parameters are related to deposition geometries and deposition rates. For each condition, process stability will be determined, the thermal cycle will be recorded, microstructures are characterized and mechanical properties are measured. Based on these characteristics, simple structures (sub-components) will be defined, and built by the deposition of successive metal layers. The effect of additional thermal cycles on the microstructure and properties will be established. Anisotropic effects on microstructure and properties due to unidirectional solidification will be considered. Furthermore, residual stresses and geometrical deviations from the originally designed structure will be determined. Experimental investigations will be accompanied by physics based microstructural and finite element thermo-mechanical models.
The obtained data sets will form the starting point to create functionally graded structures by variations in i) process conditions and ii) chemical composition. The latter will be established by multiple wire feeding. The full range of characterization techniques will be applied to determine the integrity of the construct.


Project number


Main applicant

Prof. dr. I.M. Richardson

Affiliated with

Technische Universiteit Delft, Faculteit Werktuigbouwkunde, Maritieme Techniek en Technische Materiaalws. (3ME), Materials Science and Engineering (MSE)


01/06/2017 to 31/05/2020