Chapter 9
Comparative Study of Laser Weldability
of Titanium Alloys
J. M. Sánchez-Amaya and C. Churiaque
Abstract The weldability of titanium alloys depends on their chemical composition
and microstructure. Thus, pure titanium, α alloys and α + β alloys are claimed to
have excellent weldability, although metastable β alloys have bad weldability. These
general weldability considerations are applied regardless of the joining technology,
but specific novel welding techniques, as laser beam welding, can improve this property. The main objective of this paper is to determine experimentally and precisely the
range of laser weldability of the most common three families of titanium alloys. To
carry out this study, butt welds were prepared using LBW under conduction regime,
in specimens of different titanium alloys (α, α + β, and β) with the same thickness and
size. The analyses of required input laser energy to generate full penetration welds,
metallographic examinations of welds and mechanical evaluation of the joints were
performed on welded samples. Results showed that much higher input laser energy
density was required to achieve full penetration welds in the β alloy than in the α
and α + β alloys. In addition, in both α and α + β samples, microhardness values of
the fusion zone of welds were similar to the base metal. However, the microhardness
values at fusion zone of β alloy were slightly lower than those measured at base
metal. Tensile strength tests of these welds generated good results for both α and
α + β samples (the specimens did not break at the welded area, presenting UTS
and YS values similar to the base metal). Tensile specimens of β welds, however,
presented worse results, as they broke at the weld, the load values being lower than
those obtained for its base metal. Nevertheless, LBW induced some improvements
in welds of β alloy, in comparison with other welding techniques. All these results
have allowed us to state an order of laser weldability in conduction mode, according
to which, β alloy would have a worse laser weldability than α and α + β alloys.
Keywords Laser beam welding · Titanium alloys · Laser weldability
J. M. Sánchez-Amaya (B) · C. Churiaque
Department of Materials Science and Metallurgical Engineering and Inorganic Chemistry, School
of Engineering, University of Cádiz, Cádiz, Spain
e-mail: josemaria.sanchez@uca.es
© Springer Nature Switzerland AG 2021
J. P. Davim (ed.), Welding Technology, Materials Forming, Machining
and Tribology, https://doi.org/10.1007/978-3-030-63986-0_9
299
Comparative Study of Laser Weldability
of Titanium Alloys
J. M. Sánchez-Amaya and C. Churiaque
Abstract The weldability of titanium alloys depends on their chemical composition
and microstructure. Thus, pure titanium, α alloys and α + β alloys are claimed to
have excellent weldability, although metastable β alloys have bad weldability. These
general weldability considerations are applied regardless of the joining technology,
but specific novel welding techniques, as laser beam welding, can improve this property. The main objective of this paper is to determine experimentally and precisely the
range of laser weldability of the most common three families of titanium alloys. To
carry out this study, butt welds were prepared using LBW under conduction regime,
in specimens of different titanium alloys (α, α + β, and β) with the same thickness and
size. The analyses of required input laser energy to generate full penetration welds,
metallographic examinations of welds and mechanical evaluation of the joints were
performed on welded samples. Results showed that much higher input laser energy
density was required to achieve full penetration welds in the β alloy than in the α
and α + β alloys. In addition, in both α and α + β samples, microhardness values of
the fusion zone of welds were similar to the base metal. However, the microhardness
values at fusion zone of β alloy were slightly lower than those measured at base
metal. Tensile strength tests of these welds generated good results for both α and
α + β samples (the specimens did not break at the welded area, presenting UTS
and YS values similar to the base metal). Tensile specimens of β welds, however,
presented worse results, as they broke at the weld, the load values being lower than
those obtained for its base metal. Nevertheless, LBW induced some improvements
in welds of β alloy, in comparison with other welding techniques. All these results
have allowed us to state an order of laser weldability in conduction mode, according
to which, β alloy would have a worse laser weldability than α and α + β alloys.
Keywords Laser beam welding · Titanium alloys · Laser weldability
J. M. Sánchez-Amaya (B) · C. Churiaque
Department of Materials Science and Metallurgical Engineering and Inorganic Chemistry, School
of Engineering, University of Cádiz, Cádiz, Spain
e-mail: josemaria.sanchez@uca.es
© Springer Nature Switzerland AG 2021
J. P. Davim (ed.), Welding Technology, Materials Forming, Machining
and Tribology, https://doi.org/10.1007/978-3-030-63986-0_9
299