Recent advances in high performance thermoelectric materials have garnered unprecedented attention owing to their capability of direct transformation of heat energy to useful electricity. Copper Telluride (Cu₂Te), a member of the chalcogenide family has emerged as a state-of-the-art thermoelectric material with low thermal conductivity and high thermoelectric (TE) performance, however, this material exhibits exceptional transport properties only at very high temperatures. In this study, we have investigated the synergistic effects of Ga doping on the TE performance by first principles calculations along with experimental validations. The DFT (Density Functional Theory) calculations predicted that Ga doping, within considerable limits enhanced the electrical conductivity and Seebeck coefficients in Cu₂Te. This proof of concept was validated by experimental synthesis of Ga doped Cu₂Te by simple direct annealing for shorter durations of 48 hours at 1120 ºC (~1/4^th) than in previous work and subsequent thermoelectric characterization. The enhanced electrical conductivity, thermopower, and moderate thermal conductivities led to the optimized TE performance in 3 atomic % Ga doping (Cu_1.97Ga_0.03Te), exhibiting a ZT value of 0.46 at 600 K, almost three times that of pristine Cu₂Te in this temperature range. This comprehensive study provides the platform for developing new low-cost and energy efficient TE materials with enhanced ZT performance in medium temperature applications.

High entropy alloys (HEAs) were prepared using the powder bed fusion (PBF) technique. Among titanium free alloys AlCoCrFeNiMn, CoCr_1.3FeMnNi_0.7, AlCoCrFeNi_1.3, and AlCoCr_1.3FeNi_1.3 have been further investigated. A cost comparison was done for these four alloys as well as the titanium-based alloys AlCoCrFeNiTi and AlCo_0.8CrFeNiTi. Such a comparison was done in order to evaluate the performance of the titanium-free alloys as the estimated cost of these will be less than for Ti-based HEAs. Hence, we have chosen four titanium free alloys and two titanium-based alloys for further processing. All these alloys were fabricated and subsequently characterized for phase, purity and performance. Scanning electron microscopy-based images were captured for microstructure characterization. EIS-based tests and potentiodynamic scans were performed to evaluate corrosion current. Hardness tests were performed for mechanical properties evaluation. Additional testing using factorial design tests was performed to evaluate the effects of various parameters to create better PBF-based HEA samples. EBSD tests, accelerated corrosion tests (mass loss), chemical analysis after degradation, microstructure analysis before and after degradation, and mechanical property comparison for finalized samples and other similar tests were executed. The details about all these HEAs and subsequent laser processing as well as behavior of these HEAs have been included in this study. It has been observed that some of the selected alloys exhibit good performance compared to Ti-based alloys, especially with respect to improvements in elastic constant and hardness relative to commercially pure Ti.

In this study, Zn-reinforced Mg matrix composite materials were produced via powder metallurgy by exposing them to ball milling at varying mechanical milling times. Following ball milling, the powders were cold-pressed under 600 MPa to obtain green compacts. The sintering process was carried out in a tube furnace under an argon atmosphere at 500 °C for 120 min. The effects of different milling times (2 h, 4 h, and 8 h) on particle and grain size, as well as the influence of sintering temperature and time on the microstructure, were investigated through SEM analysis. Phase evolution and changes in crystal planes occurring after ball milling were revealed by XRD analysis. SEM images show that Zn particles were homogeneously distributed within the matrix after 8 h of milling. Furthermore, it can be clearly stated that the highest hardness values were obtained from the samples produced after 8 h of milling. The sample group with the highest density, least mass loss, and lowest degradation rate was obtained from materials produced from 4 h ball milled powders. The intermetallic phase formed in the powder structure after 8 h of milling tends to reduce density and corrosion properties. The findings reveal that the addition of these alloys to pure Mg clearly enhances its hardness and density, while also imparting superior corrosion resistance. These combined improvements suggest that the developed materials hold strong potential for application in biomedical and clinical environments, where both mechanical strength and corrosion resistance are critical.

Mg–Zn–Mn-based biocomposites hold prospects as potential orthopedic material. The composition of these composites can be modulated, based on applications, by selective elemental alloying. Towards that, the addition of silicon (Si), hydroxyapatite (HA), or both is considered, followed by the consolidation method, such as spark plasma sintering (SPS). In this study, the micro-mechanical properties of Mg–Zn–Mn–(Si–HA) composites were investigated through the micro-pillar compression method. The effect of Si and HA incorporation on the mechanical characteristics and deformation mechanism was also elucidated. The microstructure of the composite presents porosity, together with different bioactive phases, such as Mg–Zn, CaMg, Mn–P, MgSi₂, Mn–Si, Mn–CaO, CaMgSi, and Ca–Mn–O. Such porous structures were determined to facilitate cell growth when used as an implant, particularly for musculoskeletal-related disabilities. The yield stress (YS) and compressive stress of the Mg–Zn–Mn–Si–HA were about 1543 ± 99 MPa and 1825 ± 102 MPa, respectively. These values were about 5.8 and 4.8 times higher, respectively, than those of Mg–Zn–Mn–HA composites (266 ± 42 MPa and 380 ± 10 MPa, respectively), and the same was observed for the elastic modulus. Besides that, alloying with HA and Si alters the deformation mechanism from brittle (for Mg–Zn–Mn–Si composites) or ductile (for Mg–Zn–Mn–HA composites) to predominant ductile failure without compromising the attained mechanical properties.