Microstructures,mechanical And Corrosion Properties,and High-Temperature Deformation Behaviors Of Pb-Mg-10Al-1B-0.4Y Alloy

In this paper,Pb-Mg-10Al-1B-Y alloys with different Yttrium(Y)contents(0wt%-1.0wt%)were prepared by melting method.The microstructure and mechanical properties of Pb-Mg-10Al-1B-Y alloys with different Y contents were tested by SEM,XRD,EPMA,WDS,tensile test and compression test,and the influence of Y on the microstructure and mechanical properties of these alloys were studied.Electrochemical and immersion corrosion tests were carried out on Pb-Mg-10Al-1B alloy and Pb-Mg-10Al-1B-0.4Y alloy with the best mechanical properties.The high-temperature deformation behavior of Pb-Mg-10Al-1B-0.4Y alloy was studied by means of hot compression simulation experiment.The constitutive equation of the alloy was constructed according to the stress-strain curves,and the hot working diagram was drawn to determine the optimal processing parameters.The results and conclusions are as follows:(1)The Pb-Mg-10Al-1B alloy without Y is mainly composed of Mg phase,Mg+Mg₁₇Al₁₂ and Pb+Mg₂Pb eutectic phases.After adding Y,Y element is uniformly distributed in the alloy as a single substance,and the microstructure becomes fine and uniform.With the increase of Y content,the grain size of the alloy decreases first and then increases.When Y content is 0.4wt%,the microstructure of the alloy is the smallest and even.(2)The tensile test results show that the tensile strength of the alloy increases obviously with the increase of Y content.As the Y content increases,the tensile strength of Pb-Mg-10Al-1B-Y alloy increases first,then decreases and finally increases.When Y content is 0.4wt%,the tensile strength is 97 MPa;when Y content is 1wt%,the elongation is the highest,which is 1.81%.The compression test results show that when Y content is 0.4wt%,the compressive strength is higher,reaching 586MPa.(3)The electrochemical test results of Pb-Mg-10Al-1B alloy and Pb-Mg-10Al-1B-0.4Y alloy in 3.5wt.%Na F,3.5wt.%Na Cl,3.5wt.%Na Br and 3.5wt.%Na I solutions show that the current density of self-corrosion of Pb-Mg-10Al-1B alloy decreases and the self-corrosion potential increases with the addition of 0.4wt%Y.The corrosion rates of Pb-Mg-10Al-1B and Pb-Mg-10Al-1B-0.4Y alloys are the fastest in Na Cl solution(121 mm/a and 103 mm/a.respectively),they are the slowest in Na F solution(42 mm/a and 31 mm/a,respectively).(4)The hot compression simulation experiments of Pb-Mg-10Al-1B-0.4Y alloy show that the flow stress of the alloy is affected by the deformation temperature,strain rate and strain.The flow stress decreases with the decrease of strain rate,decreases with the increase of deformation temperature and strain.Based on the experimental data of the stress-strain curves,two kinds of Arrhenius constitutive models based on the traditional method and the multiple linear regression method are established and compared.The results show that the Arrhenius constitutive model based on the multiple linear regression method has better stress prediction performance for the alloy.According to the hot working diagram,the best process parameters of Pb-Mg-10Al-1B-0.4Y alloy under the experimental conditions are as follows:0.001s^-1????0.01s^-1and 587 K?T?613 K.