Study On Preparation Technology Of WE43 Alloy

WE43 alloy（Mg-Nd-Y-Zr alloy）has excellent strength,creep resistance and structural stability at room temperature and high temperature.At present,it is widely used in transportation,aerospace and other fields.The research on the properties of WE43 alloy is more in-depth at home and abroad,but there are few reports on the research and development of its high-quality smelting technology.Because the alloy elements of WE43 alloy are high melting point heavy rare earth and high melting point refractory zirconium,there are many difficulties to be solved in providing batch stabilized products.In the traditional smelting process,the particle size,component fluctuation,precipitation segregation and other indicators of magnesium yttrium master alloy are poor,the oxidation inclusion is easy to be introduced in the smelting process,the Zr element has problems such as large particle aggregation in ingot products,the product composition produced by small smelting equipment is unstable,and the Research and Development of technical equipment lags behind,which can not meet the Research and Development and production needs of industrial preparation process of WE4 alloy.In order to solve the problem of poor quality of magnesium yttrium master alloy,the cathode co deposition electrolysis method is used to optimize the technology of magnesium yttrium master alloy,and a short process and low composition fluctuation electrolysis process is developed.The segregation degree of the prepared magnesium yttrium master alloy is0.3-0.7wt%,the alloy yield is more than 95%,and the alloy preparation cost is about 30%less than that of the traditional preparation process.Through the research on the modification process of magnesium zirconium alloy,it is found that dissolved zirconium plays a decisive role in grain refinement.Through technical improvement,the agglomeration of zirconium particles is reduced.The yield of zirconium is more than 80%and the grain size is less than2?m.Through the study of melting temperature,material addition,melting time,casting temperature and shielding gas concentration,combined with the actual yield of each element,alloy composition（segregation）,ICP-MS,XRD,OM,SEM and other analysis and detection means,the preparation technology of WE43 alloy with low cost and high quality is obtained.The alloy melting temperature is 750℃,the melting time is 90min,the standing time is 30min,the pouring temperature is 750℃,and the concentration of SF₆protective gas is 0.1 vol.%.Research and develop special pilot smelting furnace and corresponding smelting technology for rare earth magnesium alloy smelting requirements,PLC control zoning and accurate temperature control,and the smelting temperature is up to 850℃;The functions of smelting area,refining area and casting area of smelting equipment are optimized.The distribution of alloy elements is relatively uniform in the process of alloy smelting,and the oxidation defects and gravity segregation of alloy elements are significantly improved in the later casting process;8 protective gas circuits are arranged in zones to realize accurate flow control.It provides equipment conditions for the production of low-cost,homogeneous,pure and high-performance rare earth magnesium alloy.WE43 alloy after solution+aging（175℃×16h）heat treatment,the comprehensive mechanical properties of the alloy at room temperature reach the best,with yield strength of228.82 Mpa,tensile strength of 243.93 MPa and elongation of 8.5%;Solution+aging（175℃×16h）after heat treatment,the high temperature comprehensive mechanical properties of the alloy reach the best,with yield strength of 173.83Mpa,tensile strength of 223.92MPa and elongation of 16%.Through the improvement of process and components,combined with the results of alloy microstructure and performance test and analysis,the industrialization technology of low-cost and high-quality WE43 rare earth magnesium alloy is finally formed,the technical problems of industrialized preparation of WE43 alloy are solved,and a pilot test line with an annual output of 1500 tons of high-quality rare earth magnesium alloy is built to provide efficient technical and equipment solutions for the industrialized preparation process of rare earth magnesium alloy containing ttrium.