The Effect Of Semi-solid Processing Of The Zr-based Amorphous Alloy On Organization Structure And Mechanical Properties

Most of the bulk metallic glass(BMG), the tensile ductility and fracture toughness is very low, highly localized shear behavior makes the single BMG is usually no clear plastic deformation at room temperature, the way to a sudden catastrophic failure of rupture, constraints the BMG as advanced structural materials in engineering applications. Therefore, how to improve the BMG plasticity and fracture toughness at room temperature is a key issue for BMG in researching and developing. Since Zr-based bulk amorphous alloys currently used widely, but due to plastic constraints, which makes the system application of bulk amorphous alloys is limited. This article used Zr-Cu-Al-Ni system, through semi-solid alloy processing to improve the system's strength and plasticity, thus laying a foundation for further applications.Based on the body of Zr65Cu17.5Al7.5Ni10 based amorphous alloys,the elements Fe and Ti is added; Through copper mold suction casting method 3mm diameter alloys were prepared at different voltages, then semi-solid processing. X-ray diffraction XRD, optical microscopy OM, scanning electron microscopy SEM and computer controlled electronic universal testing machine and other technical means were used to research the microstructure of he bulk amorphous, glass-forming ability, compression mechanical properties and fracture morphology at different suction casting voltages of Zr63Cu17.5Al7.5Ni10Fe2 and Zr60Cu17.5Al7.5Ni10Ti5alloys.XRD and compression results show that the components Zr63Cu17.5Al7.5Ni10Fe2 system, the semi-solid treatment (5KV suction casting) amorphous matrix precipitate a crystal phase, as the plastic phase, forming a bulk amorphous matrix composites materials, to improve the alloy's plastic. The composite material is a micro-level dendritic dispersed in the amorphous matrix composition, but with the voltage increasing, that is semi-solid to liquid transformation process, the plastic can be decreased with the crystal phase is reduced.5KV for the system in terms of strength and plasticity of the alloy is the best. Its strength up to 1651.352MPa, plastic strain is 2.93%.For the components Zr60Cu17.5Al7.5Ni10Ti5 system, the semi-solid treatment (7KV suction-casting) alloy plastic is good,and the component is the crystal and amorphous composites. However, the system is not the highest intensity, the intensity of only 1487.411 MPa, the plastic for the system is up to 1.94%.DSC results show that for Zr63Cu17.5Al7.5Ni10Fe2and Zr60Cu17.5Al7.5Ni10Ti5 system, as the suction casting voltage is increased, semi-solid to liquid transition process, the glass forming ability of the alloys was enhanced. This also indicates that in the process, and the crystal-phase is less and less, while the amorphous component is increased. In addition, the thermal analysis results also show that the crystalline volume fraction decreases with increasing voltage.Fracture surface analysis showed that the crystalline volume fraction of amorphous phase on the mechanical properties of composite materials plays an important role, as opposed to completely amorphous alloys (8KV) of Zr63Cu17.5Al7.5Ni10Fe2 and Zr6oCu17.5Al7.5Ni10Ti5 terms bulk metallic glass matrix composite, the presence of dendritic phase in (5KV) Zr63Cu17.5Al7.5Ni10Fe2 and (7KV) Zr60Cu17.5A7.5sNi10Ti5 i stop the expansion of a single shear band, induced the formation of more shear bands and made the plastic deformation n enhanced.