The need for sustainable use of resources requires continuous improvement in the energy efficiency and development of new approaches to the design and processing of suitable materials. The concept of high entropy alloys (HEAs) has recently been extended to more general compositional complex alloys (CCAs) and multi-principal element alloys (MPEAs). One of the major challenges on the way to application of these alloys is the extensive design and selection efforts due to the great variety of possible compositions and its consequences for workability and resulting material properties. The favorable high-temperature strength of Ni-based and Co-based superalloys is ascribed to a defined γ/γ’ structure consisting of a disordered FCC A1 matrix and ordered L 12 γ’ precipitates. In the current work we extended this design concept to CCAs, allowing disordered BCC A2 and ordered B2 phases in additions or in substitution of the original γ/γ’ structure. We used a high-throughput screening approach combining CALPHAD-based computational tools with in situ alloying by means of laser cladding. Wall-type specimens with gradient composition in the system Al-Co-Cr-Fe-Ni-Ti with varying Al, Ti and Cr content were analyzed. The combined modelling and experimental screening approach was demonstrated to be a powerful tool for designing new high performance AM-ready feedstock.

In this study, bioactive glass powders were synthesized from four different types of oxides (SiO 2 , P 2 O 5 , CaO and MgO). These oxides were mixed, melted, milled and sieved to produce powders with two chemical compositions of the 31SiO 2 -11P 2 O 5 -(58-x)CaO-xMgO system. The powders were plasma sprayed onto AISI 316L stainless steel and Ti6Al4V titanium alloy substrates using a F4MB Sulzer Metco gun. The physical and mechanical properties of coatings, as well as their bioactivity were evaluated. The bioactivity tests were carried out exposing the surface of coatings to simulated body fluid (SBF) during 1, 9 and 15 days. The thickness and hardness of apatite layer produced on the surface of each coating during bioactivity tests were evaluated. The results indicate that the thickness of apatite layer formed during 15 days in SBF is between 31 and 51 µm and its hardness is between 1.5 and 1.9 GPa according to the chemical composition of feed stock powder used to manufacture the coatings. Additionally, the harness of bioglass coatings decreased around 26% after to expose them to SBF.

Atmospheric plasma and oxy-acetylene flame were used to spray alumina-titania micrometer sized particles with respectively 13 wt.% and 45 wt.% of TiO 2 (AT-13 and AT-45). Plasma spraying was also used to spray nanometer-sized- agglomerated particles (AT-13). The enthalpy of spray guns was varied to achieve coatings with different phases and structural characteristics. The influence of the different structural characteristics and the phases of coatings on their hardness and tribological behavior was then studied. The wear resistance was determined by dry elastic contact between an alumina ball, 6 mm in diameter, and the polished coated discs. The ball was moved at a linear speed of 0.1 m/s under a load of 5 N during 20,000 cycles. Drilling tests between a steel drill bit, 12.5 mm in diameter, and the coating surface were also carried out in order to determine the wear resistance under plastic contact. The wear test results showed that AT-13 coatings were more resistant than the AT-45 ones, which was due to the presence of α and γ alumina, phases presenting a high mechanical resistance. On the contrary the resistance of AT-45 coatings, consisting of Al 2 TiO 5 and Al 6 Ti 2 O 13 brittle phases of low hardness, was poorer. Under elastic contact the reduction of the wear resistance of coatings elaborated by flame spraying was not obvious, but under plastic contact the plasma sprayed coatings were more resistant than those deposited by oxy-acetylene flame.