Microstructure and strengthening mechanisms of molybdenum alloy wires doped with lanthanum oxide particles

Lanthanum oxide doped molybdenum alloy wires with different diameters were prepared by using the powder metallurgy method and press working technology. The strength were experimentally determined and related to the microstructures. The effects of the oxides mass fractions and wires diameter on the microstructures and on the mechanical properties of the molybdenum alloy wires were quantitatively investigated. Results showed that the microstructure of the doped molybdenum alloy wires will be refined with increasing the oxides mass fractions and reducing wire diameter, resulting in the increase in the yield strength. The quantitative relationships between the yield strengths and the volume fraction of lanthanum oxide particles and the subgrain sizes were presented. Calculations show that the lanthanum oxide particles strengthening effect, fine substructural strengthening effect and dislocation strengthening effect are the main strengthening mechanisms of the lanthanum oxide doped molybdenum alloy wires.