Rare Earth Of Al - Cu - Mg - Mn Alloy Microstructure And Properties Of Influence

As a reference to2A12, is applied to study Al-Cu-Mg-Mn aluminum alloy, by adding appropriate amount of rare earth elements Y and La. took available advantages of metallo graphic analysis、X-ray diffraction analysis、scanning electronic microscopy and mechanics Properties test, researched the influences on Al-Cu-Mg-Mn aluminum alloy after different Aging process and Y, La being added gradually, found an Optimum Y and La content. The results show that:1. when the content of Y inO.3%, alloy refinement effect its content increased; when the content of Y is0.3%, the alloy in as-cast microstructure grain refining and tissue homogenization effect is the most obvious, grain size from150μm to40μm and reduce the second phase occurs when Y balling phenomenon; volume of more than0.3%, with the increase of content of Y alloy in as-cast microstructure grain coarsening phenomenon began to appear; Y alloy were formed in YCu4Al8dispersed in the grain boundary, the alloy with improved performance.2. After adding rare earth Y, the hardness of the alloy and mechanics performance change, rare earth content is0.3%, the optimal mechanical properties, hardness and tensile strength are significantly increased, but with the content of Y continues to increase, mainly aging precipitation reduction, mechanical properties decreased.3. La content in the alloy is lower than0.3%, microstructure refinement effect as the level increases; when La content was0.3%refinement effect is most obvious, grain size from150μm reduced to50μm; but when the content of La is0.4%, the alloy as cast grain size began to gross. La joins the main alloy to form dispersed at grain boundary phase Al7CuLa2plus La, alloy, alloy performance improved.4. Due to the addition of La refine alloy ingot microstructure, so the hardness and tensile strength are increased, and the content of La is0.3%when the hardness and tensile strength reached the maximum value. But when La content is higher than0.3%, an excess of rare earth alloy and aluminum, and the copper, magnesium, manganese, intennetallic compound is formed gradually increased, consumption of alloy composition of the main elements of Cu and Mg, S(Al2CuMg) that aging precipitation reduction, lead alloy matrix softening, alloy lower mechanical properties.5. Al-Cu-Mg-Mn alloy after natural ageing tensile strength higher than that of the artificial aging (190℃×5h, air-cooled) intensity after22%;the grading after aging treatment, the hardness of the alloy and tensile strength than the artificial aging respectively20%and17%, description of graded aging can improve dispersion strengthening; and natural aging, alloy the classification of strength decrease slightly after aging. 6. In the same heat treatment system, add Y alloy single aging and graded aging after mechanical perfomiance are superior to add La alloy, YCu4Al8alloy strengthening effect than Al7CuLa2relative phase.