Fully amorphous Zr_(52.5)Cu_(17.9)Ni_(14.6)Al_(10)Ti_(5) bulk metallic glass(BMG) samples with a relative density exceeding 98% were fabricated via selective laser melting(SLM).High fracture stresses of around1700 MPa...Fully amorphous Zr_(52.5)Cu_(17.9)Ni_(14.6)Al_(10)Ti_(5) bulk metallic glass(BMG) samples with a relative density exceeding 98% were fabricated via selective laser melting(SLM).High fracture stresses of around1700 MPa and a reproducible plastic strain of about 0.5% were obtained for cylindrical SLM samples.The analysis of the observed serrations during compressive loading implies that the shear-band dynamics in the additively manufactured samples distinctly differ from those of the as-cast glass.This phenomenon appears to originate from the presence of uniformly dispersed spherical pores as well as from the more pronounced heterogeneity of the glass itself as revealed by instrumented indentation.Despite these heterogeneities,the shear bands are straight and form in the plane of maximum shear stress.Additive manufacturing,hence,might not only allow for producing large BMG samples with complex geometries but also for manipulating their deformation behaviour through tailoring porosity and structural heterogeneity.展开更多
Three different Cu-Zr-Co alloys, namely Cu40Zr37.5Co22.5, Cu42.5Zr45Co12.5 and Cu49Zr49Co2, were obtained by rapid cooling. The microstructure and phase formation of as-cast rods with diameters of 2 mm are compared wi...Three different Cu-Zr-Co alloys, namely Cu40Zr37.5Co22.5, Cu42.5Zr45Co12.5 and Cu49Zr49Co2, were obtained by rapid cooling. The microstructure and phase formation of as-cast rods with diameters of 2 mm are compared with those of the respective ingots. An increasing Co content stabilises the B2 CuZr phase and leads to the precipitation of a ternary Cu-Zr-Co phase. The variation of the cooling rate affects the size of the B2 dendrites as well as the volume fraction and the morphology of the interdendritic phases. The mechanical properties were determined in compression and all alloys show a certain plastic deformability despite the presence of several binary and ternary intermetallic phases. The deformation mechanisms are discussed on the basis of the microstructures and the constituent phases.展开更多
基金support from the China Scholarship Council(CSC)the support from DFG under grant nos.PA 2275/4-1,PA 2275/6-1,KU 1974/11-1 and KO 5571/1-1。
文摘Fully amorphous Zr_(52.5)Cu_(17.9)Ni_(14.6)Al_(10)Ti_(5) bulk metallic glass(BMG) samples with a relative density exceeding 98% were fabricated via selective laser melting(SLM).High fracture stresses of around1700 MPa and a reproducible plastic strain of about 0.5% were obtained for cylindrical SLM samples.The analysis of the observed serrations during compressive loading implies that the shear-band dynamics in the additively manufactured samples distinctly differ from those of the as-cast glass.This phenomenon appears to originate from the presence of uniformly dispersed spherical pores as well as from the more pronounced heterogeneity of the glass itself as revealed by instrumented indentation.Despite these heterogeneities,the shear bands are straight and form in the plane of maximum shear stress.Additive manufacturing,hence,might not only allow for producing large BMG samples with complex geometries but also for manipulating their deformation behaviour through tailoring porosity and structural heterogeneity.
基金the financial support by CNPq, Brazil, and DAAD, Germany
文摘Three different Cu-Zr-Co alloys, namely Cu40Zr37.5Co22.5, Cu42.5Zr45Co12.5 and Cu49Zr49Co2, were obtained by rapid cooling. The microstructure and phase formation of as-cast rods with diameters of 2 mm are compared with those of the respective ingots. An increasing Co content stabilises the B2 CuZr phase and leads to the precipitation of a ternary Cu-Zr-Co phase. The variation of the cooling rate affects the size of the B2 dendrites as well as the volume fraction and the morphology of the interdendritic phases. The mechanical properties were determined in compression and all alloys show a certain plastic deformability despite the presence of several binary and ternary intermetallic phases. The deformation mechanisms are discussed on the basis of the microstructures and the constituent phases.
