Laser Irradiation Induced Particle Reinforcement Of Zr-based Metallic Glass Surface And Its Mechanical Properties

Due to the unique amorphous atomic structure,metallic glasses(MGs)exhibit excellent mechanical,physical and chemical properties,and have a wide range of applications in mechanical and electronics,aerospace,chemical industry and military defense industry.MGs have higher hardness than crystalline metals,providing an opportunity for their application as contact materials,and further improvement of their surface hardness will greatly enhance the functional application of MGs in this area.Particles reinforcement is an effective method to improve the properties of MGs.To address the deficiencies in the existing particle reinforcement methods for MGs,this paper combines laser processing with the particle reinforcement and proposes a laser-induced particle reinforcement method to improve the surface hardness of Zr-based MG,using Si C particles and Si particles as the reinforcing phases.The specific research contents are as follows:(1)Experimental study of nanosecond pulsed laser irradiation of Zr-based MG surface pre-placed Si C powder was performed.The morphological observation,elemental composition analysis and phase constituents were performed using the scanning electron microscope(SEM),the energy dispersive X-ray spectroscopy(EDS),the X-ray diffractometer(XRD)and the Raman spectrometer.Characterization and analysis of mechanical properties of laser-irradiated surfaces were performed using nanoindentation tester and scratching instrument.The effects of laser power,scanning overlap rate and scanning speed on the microscopic morphology and mechanical properties of irradiated surfaces were further investigated.The experimental results showed that a Si C particle reinforced layer was generated on the surface of the Zr-based MG after laser irradiation,and the hardness of the surface matrix region reached a maximum of 28.911 GPa,which is 348% higher than the original hardness of 6.455 GPa.Meanwhile,the cross-sectional properties of Zr-based MG samples were obtained under different laser irradiation conditions.(2)Experimental study of nanosecond pulsed laser irradiation of Zr-based MG surface pre-placed Si powder was performed.The microscopic morphology,elemental distribution and phase constituents of the surface after laser irradiation were characterized,and the effects of laser irradiation parameters on the microscopic morphology and mechanical properties of the irradiated surface were investigated.The experimental results showed that a Si reinforced layer was generated on the surface of the Zr-based MG,and the laser irradiated surface hardness had a large increase.Meanwhile,the cross-sectional characterization of the irradiated samples showed that the Si reinforced layer is more tightly bonded to the Zr-based MG substrate than the Si C particle reinforced layer,and the defects are significantly reduced.(3)To take full advantage of the high hardness of the Si C particle reinforced layer and the tight bonding of the Si reinforced layer to the Zr-based MG substrate,experimental study of nanosecond pulsed laser irradiation of Zr-based MG surface pre-placed Si C-Si powder was performed.The effect of mass proportioning of pre-placed Si C-Si hybrid powders on the microscopic morphology and mechanical properties of laser-irradiated surfaces was investigated.Further,the cross-sectional properties of Zr-based MG samples after laser irradiation were investigated.The experimental results showed that a Si C-Si particle reinforced layer was generated on the laser irradiated surface of the Zr-based MG,which is tightly bonded to the Zr-based MG substrate.In summary,in this paper,Si C/Si particle reinforced layers were successfully prepared on the surface of Zr-based MGs pre-placed with Si C,Si,and Si C-Si powders fabricated by nanosecond laser irradiation.The mechanical properties of the Si C/Si particle reinforced layers were investigated.The formation mechanism of the Si C/Si particle reinforced layers was analyzed.The method proposed in this paper has the advantages of simple process flow,high processing efficiency and high degree of hardening,which provides a new technical mean for surface hardening of MGs.