First-principles calculations were performed to study the structural, mechanical, electronic and magnetic properties of Fe_(8−x)Mo_xB₄ (x = 0, 0.25, 0.5, 1, 2, 3, 4, 5, 6, 7, 8). Results show that the Mo atoms would enter the Fe₂B lattice by replacing the Fe atoms and cause a change in the crystal structure. According to the calculated formation enthalpy, all borides are thermodynamically stable; moreover, Mo would reduce the stability of Fe₂B when the Mo atomic number is less than four in the unit cell. On the whole, with the increase of Mo content, the Young’s moduli and shear moduli decrease firstly and then increase, while the bulk moduli get bigger. Although the hardness of Fe₂B would decline with increasing Mo content, Mo is an excellent candidate for improving the ductility of Fe₂B on the basis of the G/B and Poisson’s ratio ν values. The charge density plots indicate that the integral strength of the linear boron chains in [002] orientation is reduced in Mo-alloyed Fe₂B. The toughness improvement of Fe₂B would be attributed to the evolutions of B–B bonds, Fe/Mo–B bonds and Fe/Mo–Fe bonds, which may induce the deflection of the Fe₂B cleavage plane. Besides, the magnetic moments of these borides monotonically decrease with the increase in Mo content.

The comprehensive performance of Al-Zn-Mg-Cu alloy can be significantly improved by a proposed novel thermo-mechanical treatment (NTMT). The influence of the NTMT on the properties and microstructure was investigated by tensile test, corrosion resistance test, X-ray diffraction (XRD), and transmission electron microscopy (TEM). Results show that Al-Zn-Mg-Cu alloy treated by the NTMT can obtain an excellent combination of strength and ductility. The highest yield strength and ultimate tensile strength reached 643 MPa and 664 MPa respectively, and the elongation was 9.7%. Meanwhile, electrochemical corrosion resistance and intergranular corrosion resistance in the aluminum alloy can be improved after the NTMT. The mechanism of the excellent combination of strength and ductility is thought to be the synergistic effect of dislocations substructures, texture configuration, and nanoprecipitates. The improvement of intergranular corrosion resistance of the aluminum alloy is caused by changes in the micro-morphology of grain boundary precipitates after the NTMT, which can block anodic dissolution channels along grain boundaries to reduce the rate of anodic dissolution and avoid hydrogen embrittlement.