Study On Microstructure And Mechanical Properties Of High Manganese ZA35 Alloy By Spray Forming Process

In this paper, ZA35-3. 5 Mn alloy was adopted as research object by adding Mn element, formed by spray deposition and extruding. According to the principle of orthogonal test, the orthogonal chart L₉(3⁴) of heat treatment was designed. A better heat treatment process could be obtained with applying direct analysis, that is 385℃×5h+120℃×7h. According to it, having heat treatment on metal mould and spray-deposition alloys, the mechanical properties and microstructure were tested. In addition, the wear and friction properties were also studied.The results indicate that in this experiment that ZA35-3. 5Mn alloy formed by spray deposition has a more significant magnification than by metal mould. The strength of ZA35-3.5Mn alloy by spray deposition is 484.2MPa, which is 41.4% higher than that by metallic mould at room temperature; At 150℃, the strength of ZA35-3.5Mn alloy by spray deposition is 236.8MPa, which is 53.3% higher than that by metallic mould; At 180℃, the strength ZA35-3.5Mn alloy by spray deposition is 208.9MPa,which is 63.6% higher than that by metallic mould. The difference elongation of ZA35-3.5Mn alloy between by spray deposition and metallic mould is not very obvious, which is 2.85% and 1.25%. At 150℃, the elongation of ZA35-3.5Mn alloy by spray deposition is 23.5%,which is 15.9more than that by metallic model; At 180℃, the elongation of ZA35-3.5Mn alloy by spray deposition is 29.41%, which is 15.5 more than that by metallic mould.According to the analysis on the microstructure, the results show that the phase compositions of ZA35-3.5Mn alloy by spray deposition areα-A1,μ-Zn and Mg32(AlZn)49, which can illustrate Mn solute in the matrix sufficiently. After heat treatment, Al₁₁ Cu₅Mn₃, CuMnZn and Mg₃₂(A1Zn)49 are precipitated as complex resist heat phase. These phases which distribute in the matrix dispersely can make the matrix strengthened and they also have a effect on improving the elevated mechanical properties of Zn-A1 alloy.To compared with alloy by metal mould, the friction coefficient of ZA35-3.5Mn alloy by spray deposition reduces to 16.69% and the wear extent reduces to 54.19% at the same rotation speed. When applying load is the same, the friction coefficient ZA35-3.SMn alloy by spray deposition reduces to 17.37% and the wear extent reduces to 50.24%. Rich Mn phase as hard phase can bear heavier load, which make ZA35-3.5Mn alloy by spray deposition having better wear and friction properties.