Metastable β-Ti alloys with non-toxic and low-cost alloying elements, with high biocompatibility and improved mechanical properties, are being developed globally for biomedical applications. Howerver, there is still limited published work on Ti-Mo and Ti-Mo-Fe alloys with high Mo content and low cost alloying element with high strength designed for biomedical applications such as vascular stents. Thus, the current study uniquely investigates the combined influence of Fe addition and theoretical methods on β stability and mechanical performance of Ti-Mo alloys with high Mo content vascular stents. Two metastable β-Ti alloys, namely, binary Ti-20Mo wt% (referred to as Alloy 1) and ternary Ti-16.5Mo-1.1Fe wt% (referred to as Alloy 2), were designed using the theoretical predictive methods such as the molybdenum equivalence (Moeq), the average Bo-Md method, and the electron-to-atom ratio (e/a). Microstructural characterization and tensile properties of the alloys after solution treatment at 1100 °C and quenched in ice-brine were analysed. The X-ray diffraction (XRD) patterns and optical micrographs showed stability of the β phase in both alloys due to similarity in e/a ratio value and a slight difference in Moeq. Alloy 1 showed a high ultimate tensile strength (UTS) of 920 MPa and yield strength (YS) of 906 MPa, whereas a much lower UTS of 540 MPa was observed in Alloy 2. The elastic modulus decreased from 85 GPa in Alloy 1 to 74 GPa in Alloy 2, while micro-Vickers hardness increased significantly from 353 Hv_0.5 in Alloy 1 to 428 Hv_0.5 in Alloy 2. The high strength and modulus in Alloy 1 illustrated that the alloy could be considered as a potential alloy for biomedical applications such as those in vascular stents.

MnPt’s exceptional stability and extremely high Néel temperature have generated a lot of interest in data storage applications. Previously, it was reported experimentally that the MnPt alloy shows ferromagnetic (FM) behavior at room temperature. In this study, the effects of partial substitution of Pt with Pd, Au, and Ag on magnetic properties is investigated using density functional theory. The stability of Mn₅₀Pt_50−xM_x (M = Pd, Au, Ag, x = 6.25, 12.5, 18.75) alloys was assessed by determining their thermodynamic, magnetic, and mechanical properties. The calculated lattice constants of Mn₅₀Pt₅₀ agree well with available theoretical results. The Mn₅₀Pt_50−xM_x alloys’ formability was assessed by measuring the thermodynamic stability using the heat of formation. It was found that B2 Mn₅₀Pt_50−xPd_x alloys (0 ≤ x ≤ 18.75) are thermodynamically stable due to the negative heat of formation close to that of a pristine MnPt alloy. Based on the elasticity results, the B2 Mn₅₀Pt_50−xPd_x is most likely to undergo martensitic transformation for the entire considered composition range. From the calculated values of the Poisson′s ratio, it is shown that an increase in Pd, Ag, and Au effectively improves the ductility of the B2 Mn₅₀Pt_50−xM_x compounds. It was revealed that ferromagnetism is maintained with Pd addition but significantly reduced in the case of Au and Ag. Thus, this work showed that density functional theory can be exploited to propose new possible compositions for future magnets in spintronic applications.

The global liquified natural gas (LNG) storage market size is projected to reach USD17.5 billion by 2025. Currently, owed to its high toughness, tensile strength, and excellent weldability, the 9% nickel steel is the most used in building infrastructure for cryogenic applications such as the construction of tanks and pipes for storage and transportation of LNG. However, this alloy is not readily available because of its complex production process and high cost. This provides an opportunity for suitable alternative materials to build infrastructure for cryogenic applications. Among strong contenders is the Fe-Mn based alloys, which have sparked global interest due to their desirable properties such as relatively lower density, low cost, high toughness and strength, due to a high manganese (Mn) content. These attractive properties render Fe-Mn based alloys preferred candidates to replace traditional steels in engineering applications in which strength-weight ratio is critical. In response, as a build-up to designing and developing austenitic Fe-Mn alloys, the present study employed density functional theory (DFT) based first-principles computational materials modelling technique to investigate the structural, thermodynamic, and magnetic properties of binary Fe-Mn alloy composition in competing FCC, HCP, and BCC crystal structures. Using this approach, it was possible to unravel the key underlying elastic properties that are directly correlated to experimental tensile strength and high toughness in binary Fe-Mn alloys. Besides successfully validating the existing experimental data, the current predicted properties and the deployed approach will serve as a benchmark from which further alloying required to improve other properties will be conducted.

The alloying effect of three elements, namely Al, Cr and Zn, on the Pt site of L1₂ Cu₃Pt phase was investigated using DFT (density functional theory) based first-principle calculations in attempt to stabilize it in the form of L1₂ Cu₃Pt_1-xY_x ternary alloy. On the basis of phase stability and elastic properties, the substitution behaviour of all three alloying elements were compared with properties of thermodynamically sluggish Cu₃Pt phase. The calculated heats of formation reveal that the thermodynamic phase stability is gradually enhanced with increasing content of aluminium alloying and diminished with increasing content of zinc and chromium. In this current work, the stress-strain approach was used according to Hooke’s law to calculate elastic properties such as elastic constants, Young’s modulus E, shear modulus G, bulk modulus B and Poisson’s ratio v, as they play an important role to investigate the resulting mechanical properties. The calculated results show that alloying with all three elements maintains the mechanical stability criteria of cubic crystals. Considered L1₂ Cu₃Pt_1-xY_x ternary alloys exhibit the most ductile character with Al addition, followed by Cr, whereas introduction of Zn yielded lowest ductility at higher compositions.