This paper presents the results of functionally graded Ti6Al4V-Mo alloy manufactured with directed energy deposition called CLAD ® (Construction Laser Additive Direct) process. Single track width sample with five gradients of composition, from 0 to 100 wt.% Mo, was manufactured using a coaxial nozzle. Both Ti6Al4V and Mo ratios were modified with a 25 wt.% increase or decrease in the chemical composition of each gradient. A two-powder feeder was used to input the correct ratio of each powder, so as to obtain the desired chemical composition. XRD analysis allowed to define the phases present in each deposition, as well as the lattice parameter. SEM observations showed microstructural evolution from 25 wt% Mo on, namely where the ␤-phase becomes dominant. Moreover, dendrites appear from 50 wt.% Mo on. Microhardness analysis revealed variation along the deposition depending on the chemical composition. The homogeneity of the powder mixture under laser beam was highlighted thanks to tomography on the manufactured samples, which validates the processability of functionally graded material (FGM) by CLAD ® process.

Biocompatible beta-titanium alloys such as Ti-27.5(at.%)Nb are good candidates for implantology and arthroplasty applications as their particular mechanical properties, including low Young's modulus, could significantly reduce the stress-shielding phenomenon usually occurring after surgery. The CLAD® process is a powder blown additive manufacturing process that allows the manufacture of patient specific (i.e. custom) implants. Thus, the use of Ti-27.5(at.%)Nb alloy formed by CLAD® process for biomedical applications as a mean to increase cytocompatibility and mechanical biocompatibility was investigated in this study. The microstructural properties of the CLAD-deposited alloy were studied with optical microscopy and electron back-scattered diffraction (EBSD) analysis. The conservation of the mechanical properties of the Ti-27.5Nb material after the transformation steps (ingot-powder atomisation-CLAD) were verified with tensile tests and appear to remain close to those of reference material. Cytocompatibility of the material and subsequent cell viability tests showed that no cytotoxic elements are released in the medium and that viable cells proliferated well.

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Steels obtained by the thermo–mechanical control process (TMCP) possess a higher level of strength than conventional normalized steels due to the fine‐grained microstructures generated during TMCP. Such enhancement opens ways to decrease metal construction weight. At the same time, TMCP steels have less thermal stability, in connection with a lot of factors affecting and governing grain growth during the heating of TMCP steels. Herein, the effects of the welding thermal cycle (WTC) on the structure and properties of TMCP steels of ferritic–perlite (S460M) and bainitic (alform 620M) types are systematically investigated.

The microstructure of bulk samples prepared by CLAD® additive manufacturing of Ti-6Al-4V (Ti64) powder have been investigated by means of SEM and phase reconstruction. The CLAD® technique (laser blown powder processing) developed at IREPA LASER provides very high cooling rate promoting the formation of the martensitic ' phase in the form of thin needles. Using Merengue 2 software developed at LEM3, the analysis of the martensitic phase orientation by EBSD enables the reconstruction of the primary -phase that formed at high temperature. Microstructural observations performed at various locations within the samples revealed marked heterogeneities in the microstructure. After the first deposited layer characterized by fine and equiaxed grains, the grains located in the central region of the samples tend to grow in a direction perpendicular to the deposited layer plan with a coarse columnar structure. By opposition, the grains on the sample side were found to grow at angle of about 60° from the deposited layer plan. The main difference with others additive manufacturing techniques is that, only a weak crystallographic texture was detected in these samples prepared by CLAD®.