The Microstructure Evolution And Mechanical Properties Of Al-Cu,Al-Si Alloys Modified By Fe,Zr Glasses

As a result of aluminum alloy have been widely used in the aerospace,automotive, machinery industries.Each industrial developed countries has been takeconstantly efforts to make the properties and the processing technology of aluminumalloy reached a new level in order to meet the requirements of different industries.Inrecent years, the deterioration of Al-Cu and Al-Si alloy has caused wide publicconcern over the material workers, they have use the Na salt,P,S and rare earthcompounds to modify aluminum alloy and get an abvious effect. At present, due to theperformance requirements for aluminum alloy is higher and higher, we need todevelop new alterative to meet the needs of higher aluminum alloy applications.Inaddition, there are not so many schoolers use glass as inoculant modification ofaluminum alloy.Therefore, in order to enrich metamorphic mechanism of aluminumalloy, at the same time to expand the application of modified alloy.The research theinfluence of the microstructure and mechanical properties of glass modified Al-Cu,Al-Si alloy has a high application value.My paper take ZL205A alloy and A390alloy as the research object, reveals theFe, Zr glass modified Al-Cu, Al-Si alloy’s microstructure, room temperature tensileproperties.Explore the metamorphism in the alloy θ’ the influence of the number, sizeand distribution of the precipitated phase.Put forward the metamorphic casting ofAl-Cu, Al-Si alloy modified mechanism and strengthening mechanism.The mainconclusions are as follows:1It revealed different system of the crystallization of glass phase particles in theprocess of-Al crystallization, which is the core of the heterogeneous nucleation,refine the-Al dendrite. ZrCuAlNiLa glass modified ZL205A alloy, Fe based glassdepartment of metamorphic effect is significant for A390alloy.i) ZrCuAlNiLa amorphous metamorphic ZL205A alloy, in the case of metamorphic time for1min, the organization chart of small grains to about40μm insize isometric crystal. As the extension of modified time, organization by isometricgradually transformed into dendrites.ii) Al-P and ZrCuAlNi amorphous composite modified A390alloy, the size ofprimary silicon change is not big, about20μm, more uniform distribution. Eutecticsilicon clusters form has long needle, after T6heat treatment of the alloy, the eutecticsilicon and the short rods or dots.iii) Al-P and FeBSi composite modified A390alloy, deterioration of theorganization of the size of primary silicon in about20μm, obtuse Angle will become.Eutectic silicon clusters by the original form into a long needle, after T6heattreatment of the alloy, the eutectic silicon and the short rods or dotted andhomogeneity.2It revealed different system of glass midified of Al-Cu, Al-Si alloy canobviously improved the room temperature tensile properties, the ZrCuAlNiLaamorphous metamorphic ZL205A alloy, the tensile properties of the amorphous Fedepartment of metamorphic A390alloy increase more significantly.i) Add0.2wt.%(Zr55Cu30Al10Ni5)97.2La2.8amorphous metamorphic ZL205A alloy1min of tensile properties to achieve the optimal, tensile strength is532.9MPa,metamorphic alloy increased than72.1MPa, the fracture strain reached15.8%, thannot metamorphic alloy increased by143%.ii)Add0.5wt.%Al-P+0.2wt.%Zr based glass composite for45s Al-Si alloyachieved274.6MPa in tensile strength which is the best effect;Elongation ratereached2.65%.Metamorphism Al-Si alloy after T6heat treatment, adding0.5wt.%Al-P+0.2wt.%Zr metamorphosed amorphous composite45s after tensilestrength is363.2MPa.Fracture should be variable to achieve the highest2.81%.iii)Add0.5wt.%Al-P+0.1wt.%Fe metamorphosed amorphous composite60minAl-Si alloy282.4MPa tensile strength to achieve the best effect, elongation ratereached3.37%.Metamorphism Al-Si alloy after T6heat treatment, adding0.5wt.%Al-P+0.1wt.%Fe metamorphosed amorphous composite60min after tensilestrength reached380.6MPa, the elongation reaches up to3.57%.3It revealed the influence of the number, size and distribution of the precipitatedphase of different system of glass modified alloys’ θ’.It found that the size of theprecipitated θ’ phase becomes smaller, distribution is more homogeneous.i) After amorphous metamorphic θ’ phase become more short, the averagethickness is about10nm, the average length of70.29nm, and size distribution becomes more uniform.ii) FeBSi amorphous and Al-P compound metamorphism Al-Si alloy after θ’phasechange more short, number and density increases, the average thickness of about20nm, the average length was60.44nm, and size distribution becomes more uniform.4It revealed different system of glass modified Al-Cu, Al-Si alloy’smetamorphic mechanism and strengthen the mechanism.i)Amorphous metamorphic mechanism of Al-Cu, Al-Si alloy is: the amorphousafter joining aluminium alloy melt, crystal into tiny crystallization phase quickly,gradually dispersed homogeneously in aluminum melt crystallization phase, theuniform will crystallization particles during alloy solidification at the core of-Alphase heterogeneous nucleation, greatly increasing the nucleation particles inaluminum alloy melt, significantly increase the nucleation rate, the elaboration ofα-Al dendrite obviously.ii)Amorphous modify aluminum alloy strength mechanism to: fine-grainstrengthening and Orowan strengthening work together.①Fine-grain strengthening: It formed more grain number, grain boundaryincreases, hinder the dislocation, so it bring the strong toughness of the alloy onmacro performance.②The Orowan strengthening: θ’precipitated phase can pin the dislocation andhinder dislocation motion, It can also cause proliferation ofv dislocation, so increasedalloy dislocation of storage capacity.