Microstructure and Strengthening Mechanism of Oxide Lanthanum Dispersion Strengthened Molybdenum Alloy

Abstract

Sintered molybdenum is widely used in the industry as an electrode for smelting furnace of glass and refractory, the crucible of rare earth metallurgy, and the thimbles for producing seamless steel tube and so on because of its strength at elevated temperature, good thermal properties, low sputtering yields and resistance to swelling. These unique properties of molybdenum make it a good candidate as a refractory metal. However, its further applications were limited by the brittleness characteristic and therefore many new molybdenum alloys were developed for improving ductility, among which the oxide dispersion strengthened molybdenum alloy (ODS Mo) is especially of interest. The ODS Mo, prepared by adding a proper amount of rare earth oxides (La 2 O 3 , Y 2 O 3 etc.) and by deforming to a large amount, exhibits a much higher recrystallization temperature than commercial pure molybdenum, [1±6] which makes ODS Mo show not only superior non-sag property and creep resistance at high temperatures but also superior strength and ductility at low temperatures as compared with the pure molybdenum. [7±9] Many explanations have been suggested on the strengthen mechanism of oxide dispersion strengthened molybdenum alloy. Hiraoka et al. attributed the improvement of low-temperature brittleness to the elongated coarse grain structure, [7] Deng shiqiang et al. thought that rare earth could decrease the density of C, N, O on the grain boundaries, [8] whereas

Interfacial microstructure and shear strength of Ag nano particle doped Sn–9Zn solder in ball grid array packages

“…Later some of the AgZn 3 IMCs agglomerate together to form micrometer-sized AgZn 3 IMCs in the bulk solder. Due to a second phase dispersion strengthening mechanism [22] of AgZn 3 intermetallic compound particles, the Ag doped solder showed a higher strength than the undoped solder. The shear strength of 0.3 wt% and 1 wt% Ag nano particles content solder joints after one reflow cycle were about 45.8 MPa and 48.9 MPa, respectively.…”

Microstructural and mechanical characterization of annealed tungsten (W) and potassium-doped tungsten foils

“…Here, oxide-dispersion strengthened (ODS) tungsten materials [11][12][13] or potassium (K)-doped tungsten materials [14,15] may offer a solution. The latter is what we assess within this study.…”

The influence of addition of Al nano-particles on the microstructure and shear strength of eutectic Sn–Ag–Cu solder on Au/Ni metallized Cu pads

“…The higher shear strength of the Al nano-particles doped solder joints may be attributed to the formation of the fine Cu 6 Sn 5 , Ag 3 Sn and Au-Sn IMCs that are dispersed throughout the ␤-Sn matrix at the top surface of the Sn-Ni-Cu intermetallic compound layers. The presence of such fine particles can act as obstacles for the movement of dislocations and subsequently strengthening due the dispersion of these particles [26] can be considered as a plausible explanation for the higher strength in nano-doped solder joints compared with that of the undoped joints. The shear strengths of solder joints containing 0.5 and 3 wt% Al nano-particles after one reflow cycle were about 38.8 and 41.5 MPa, respectively and their shear strengths after 16 reflow cycles were about 36.4 and 38.5 MPa, respectively.…”