Hot Deformation Behavior And Processing Maps Of BFe30-1-1 Alloy

BFe30-1-1 alloy is one of copper nickel alloy, with a small amount of Fe and Mn.The addition of Fe and Mn can improve the grain refinement and the machinability of the alloy. BFe30-1-1 alloy can resist corrosion and cracking, and has the ability resistly the flow of seawater and seawater corrosion resistance.BFe3 0-1-1 alloy is an ideal material for marine equipment manufacturing, which used in marine industry, ship manufacturing, petrochemical, energy and defense industry and other fields,especially in some key parts of marine corrosion has been widely used. The alloy is used in more and more fields, and its usage is increasing year by year.With the development of technology, it is necessary to use more excellent materials in harsh environment. Therefore, it has great significance to select the best processing parameters, and it can be used to obtain accurate microstructure and improve the properties of the alloy.Hot deformation behavior of BFe30-1-1 alloy was investigated in the temperature range from 750? to 1000? and in the strain rate rage from 0.1s-1 to 10s-1 by compression tests on the Gleeble-1500D simulator. The true stress-strain curve for BFe30-1-1 alloy was acquired by the test, and the law between deformation temperature, strain rate, deformation and the flow stress was analyzed. The constitutive deformation equation of BFe30-1-1 alloy was established by analyzing the change rule of flow stress and strain rate,and the critical conditions of dynamic recrystallization was obtained. Based on the processing maps of the alloy under different strain,the optimum processing range of the alloy can be obtained by combining the microstructure of the hot deformed specimen.The main results obtained in this topic are as follows:(1) The rheological stress curve of BFe30-1-1 alloy has sharp and flat two stages in the isothermal compression deformation, which shows the characteristics of work hardening and dynamic softening.The flow stress was significantly affected by deformation temperature and strain rate.The alloy has positive strain sensitivity. Flow stress of the material gradually increased with strain rate increasing, the flow stress of materials showed decreased trend with the deformation temperature increasing.(2) Based on modified hyperbolic sine model modification, the structure factor A and the activation energy Q of BFe30-1-1 alloy were established, and A=4.586 109, Q= 177.03KJ/mol. Finally, the constitutive equation of the alloy was established.(3) The dynamic recrystallization critical condition of BFe30-1-1 alloy during hot deformation was determined. The critical strain is proportional to the Zener-Hollomon parameter, and decreased with the increase of deformation temperature and the decrease of strain rate.(4) Based on the dynamic material model (DMM),processing maps of BFe30-1-1 alloy under different strain were constructed. By comparing those processing maps shows that: the instability area of BFe30-1-1 alloy was significantly affected by strain,the temperature range of rheological instability was increased with the increase of strain, and when the strain rate increases to 0.8,the high strain rate region is basically the rheological instability area, the range of the flow instability area and the machining safety area may be changed; however, the power dissipation coefficient is not sensitive to the change of strain, the distribution of power dissipation coefficient is similar and the numerical value is smallerunder different strain conditions.(5) The processing map for the whole hot deformation of BFe30-1-1 alloy was analyzed, combing with the metallographic sample. The deformation mechanism of the microstructure of the alloy was dynamic recrystallization in the safe area during hot deformation, however, the deformation mechanism of the instability area is flow localization. The safe passage of the alloy was characterized by the whole processing map during hot deformation,and the most suitable temperature is from 910? to 950?and strain rate rage is from 0.01 s-1 to 0.1 s-1 for BFe3-1-1 alloy.