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以Si粉和6061Al合金粉末为原料,采用机械球磨-常压烧结工艺制备硅颗粒含量(质量分数)为50%的颗粒增强铝基复合材料,利用扫描电镜和X射线衍射仪分析不同温度下烧结的复合材料结构与物相组成,并测试材料的密度、抗弯强度、硬度及热膨胀系数等性能。结果表明,通过球磨可获得成分均匀的Si_p/6061Al复合粉体。烧结温度为700℃时,50%Si_p/6061Al复合材料仅含少量Al_2O_3杂质,Si相分布均匀,呈半连续骨架结构,Si颗粒与6061Al基体合金结合良好,材料中孔隙的数量和尺寸都最小。在680~750℃温度范围内,随烧结温度升高,50%Si_p/Al复合材料的致密度及抗弯强度先增大后降低,在700℃烧结的50%Si_p/6061Al复合材料具有优异的综合性能,其致密度、抗弯强度、硬度(HB)、热膨胀系数(室温)分别为96.4%,310.8 MPa,225.4和7.43×10~(-6)/K。
Using Si powder and 6061Al alloy powder as raw materials, the particle reinforced aluminum matrix composites with 50% silicon content (mass fraction) were prepared by mechanical ball milling and atmospheric pressure sintering. The microstructures of the composites were analyzed by scanning electron microscopy and X-ray diffraction. Of the composite material structure and phase composition, and test the material density, bending strength, hardness and thermal expansion coefficient and other properties. The results show that Si_p / 6061Al composite powders with uniform composition can be obtained by ball milling. When the sintering temperature is 700 ℃, the 50% Si_p / 6061Al composite contains only a small amount of Al_2O_3 impurities and the Si phase is uniformly distributed and has a semi-continuous skeleton structure. The Si particles and the 6061Al matrix alloy are well bonded, and the number and size of the pores in the material are the minimum. The compactness and flexural strength of 50% Si_p / Al composites first increase and then decrease with the increase of sintering temperature in the temperature range of 680 ~ 750 ℃. The 50% Si_p / 6061Al composites sintered at 700 ℃ have excellent Its comprehensive properties are as follows: density, flexural strength, hardness (HB) and thermal expansion coefficient (room temperature) are 96.4%, 310.8 MPa, 225.4 and 7.43 × 10 -6 / K, respectively.