Wire-Based Additive Manufacturing of Ti-6Al-4V Using Electron Beam Technique
Artikel i vetenskaplig tidskrift, 2020

Electron beam freeform fabrication is a wire feed direct energy deposition additive

manufacturing process, where the vacuum condition ensures excellent shielding against the

atmosphere and enables processing of highly reactive materials. In this work, this technique

is applied for the alpha+beta -titanium alloy Ti-6Al-4V to determine suitable process parameter for robust

building. The correlation between dimensions and the dilution of single beads based on selected

process parameters, leads to an overlapping distance in the range of 70–75% of the bead width,

resulting in a multi-bead layer with a uniform height and with a linear build-up rate. Moreover, the

stacking of layers with different numbers of tracks using an alternating symmetric welding sequence

allows the manufacturing of simple structures like walls and blocks. Microscopy investigations reveal

that the primary structure consists of epitaxial grown columnar prior beta-grains, with some randomly

scattered macro and micropores. The developed microstructure consists of a mixture of martensitic

and finer alpha-lamellar structure with a moderate and uniform hardness of 334 HV, an ultimate tensile

strength of 953 MPa and rather low fracture elongation of 4.5%. A subsequent stress relief heat

treatment leads to a uniform hardness distribution and an extended fracture elongation of 9.5%, with

a decrease of the ultimate strength to 881 MPa due to the fine alpha-lamellar structure produced during

the heat treatment. Residual stresses measured by energy dispersive X-ray di raction shows after

deposition 200–450 MPa in tension in the longitudinal direction, while the stresses reach almost zero

when the stress relief treatment is carried out.

mechanical properties

titanium alloys

additive manufacturing

residual stresses

wire feed process

electron beam

Författare

Florian Pixner

Fernando Warchomicka

Patrick Peter

Axel Steuwer

Magnus Hörnqvist Colliander

Chalmers, Fysik, Mikrostrukturfysik

R. Pederson

Norbert Enzinger

Materials

1996-1944 (ISSN)

Vol. 13 3310-

Ämneskategorier

Annan materialteknik

Metallurgi och metalliska material

Styrkeområden

Materialvetenskap

DOI

10.3390/ma13153310

Mer information

Senast uppdaterat

2020-10-15