Improved mechanical properties of W-La2O3 alloys for diamond wire busbars originating from lanthanum boride incorporation

To address the issues of insufficient strength and brittleness in traditional W-La 2 O 3 alloys for diamond wire busbars, this work highlights a composite strengthening strategy by inducing La 2 O 3 and LaB 6 at the same time. A systematic comparison was conducted on the composition and microstructure evolution as well as the corresponding compressive properties. The results show that the additional LaB 6 triggers the grain refinement of W with the grain size reduced from 29.96 μm to 22.35 μm via the in-situ formation of fine La 2 O 3 particles. Moreover, LaB 6 also promotes the generation of γ-fiber texture associated with dynamic recrystallization during thermal processing. The as-obtained alloy (W-La 2 O 3 -LaB 6 ) exhibits a compressive strength of 2562.2 MPa in the as-rotary forged state, 408.5 MPa higher than that of the traditional alloy(W-La 2 O 3 ). Concurrently, the corresponding fracture mode transforms from intergranular brittle fracture to transgranular ductile fracture. By virtue of the synergistic effect of multiple strengthening and regulating mechanisms including second-phase strengthening, grain refinement strengthening and texture regulation, LaB 6 efficiently improves the compressive properties and processability of W-La 2 O 3 alloys. This work provides a technical support for the development of high-performance photovoltaic tungsten wire busbars with a low wire breakage rate.