Study Of Glass Forming Ability And Properties Of Ni-based Amorphous Alloys

Ni-based amorphous alloys have great application prospects in many fields such as power engineering,electronic communication,aerospace,electrochemistry,etc.due to their excellent properties such as high strength,high hardness and great elastic limit.However,the smaller amorphous formation ability,higher dependence on raw material purity,and cost limit the development of Ni based amorphous alloys.Therefore,in order to achieve the engineering application of Ni based amorphous alloys,this article took the Ni-Si-B alloy system as the research object and explored the amorphous formation ability of the Ni-Si-B alloy system.Moreover,the high-temperature purification process using B₂O₃ flux was used to purify Ni-P alloy,and the formation ability and mechanical properties of the Ni_68.6Cr_8.7Nb₃P₁₆B_3.2Si_0.5 amorphous alloy were investigated.The conclusions are as follows:1.The Ni-Si-B alloy system was studied,and it was found that Ni₈₀B₁₄Si₆,Ni₈₀B₆Si₁₄,Ni₇₅Cr₅B₆Si₁₄,Ni₇₀Cr₁₀B₆Si₁₄ and Ni₆₅Cr₁₅B₆Si₁₄ alloy thin strips were all completely amorphous alloys.The industrial Ni-P alloys were added to the Ni-Cr-Si-B alloy.It was shown that the Ni_68.6Cr_8.7Nb₃P₁₆B_3.2Si_0.5 alloy thin strip was a completely amorphous alloy,and the bulk alloy of Φ2 mm was an incomplete amorphous alloy.The actual composition of the alloy ingot differed considerably from the nominal composition,and the content of impurity elements was high.2.The Ni-P alloy was purified by heat treatment at 1200℃with B₂O₃ flux for 120minutes.The study found that the P element content in the purified Ni-P alloy was 17.7wt.%,with almost no loss,and the Al impurity content was 180 ppm,a decrease of30.77%.The Ni-P alloy was purified by induction heating at 1200℃using B₂O₃ flux for 10 minutes.After purification,the P element content was 17.7 wt.%,and the Al element content was only 50 ppm,a decrease of 80.77%.The results showed that the purification effect of induction heating melting was better.3.The glass forming ability of Ni_68.6Cr_8.7Nb₃P₁₆B_3.2Si_0.5 amorphous alloys prepared by high temperature purification Ni-P alloy was analyzed.It was found that Ni_68.6Cr_8.7Nb₃P₁₆B_3.2Si_0.5 alloy thin strips and Φ3 mm,Φ4 mm,Φ5 mm bulk alloys were fully amorphous alloy.The actual composition of the alloy ingots did not differ from the nominal composition.The glass forming ability of Ni_68.6Cr_8.7Nb₃P₁₆B_3.2Si_0.5amorphous alloy was improved by using high temperature purification Ni-P alloy with B₂O₃ flux.The Vicker’s hardness of Ni_68.6Cr_8.7Nb₃P₁₆B_3.2Si_0.5 bulk amorphous alloy was 671 kg/mm²,the compressive strength was 2406 MPa,and the Young’s modulus was 142 GPa.4.The crystallization kinetics of Ni_68.6Cr_8.7Nb₃P₁₆B_3.2Si_0.5 bulk amorphous alloys were investigated,and it was found that the dependence of the crystallization process on the rate of temperature increase was greater than that of the glass transition on the rate of temperature increase,the kinetic effect of crystallization was more pronounced than that of the glass transition.The crystallization was dominated by the diffusion-controlled three-dimensional growth when the rates of temperature increase were 10K/min and 20 K/min.When the heating rates were 30 K/min,40 K/min and 50 K/min,the crystallization process was dominated by the growth of small particles.