液固分离法制备Al-65vol%Si电子封装材料组织及性能

Microstructure and properties of Al-65vol%Si alloy fabricated by a process of liquid and solid separation

采用液固分离法制备了Al-65vol%Si电子封装材料,借助扫描电镜、透射电镜等手段分析了合金中Si相的形态分布、界面及断口形貌,测定了合金的热膨胀系数、热导率及抗弯强度。结果表明:Al-65vol%Si合金组织中硅相颗粒分布均匀,形状规则呈近团球状和短杆状,Al/Si两相界面光滑、平直,无缺陷。合金密度2.4 g/cm3,室温下的热导率(TC)为119.5 W/(m.K),热膨胀系数(CTE)从50℃到400℃在6.5×10-6～11.3×10-6/K范围内稳定增加,抗弯强度为132 MPa,Si相的脆性断裂为主要断裂方式。Al-65vol%Si合金性能满足电子封装要求。

Al-65vol%Si alloy applied in electronic packaging was prepared by the method of separation of liquid phase and solid phase in semi-solid alloy during compression deformation.Morphology and distribution of primary Si phase,Al/Si interface and fracture surface were examined,and coefficient of thermal expansion（CTE）,thermal conductivity（TC） and bending strength of the alloy were tested.The results show that primary Si phase distributes uniformly in Al matrix,irregular corners and edge of the primary Si are dissolved during the liquid and solid separation,size of Si phase is reduced and its shape is regular.Interface between primary Si and Al matrix is smooth,straight and free from flaws.Al-65vol%Si alloy so prepared has a low density of 2.4 g/cm3,its CTE changes from 6.4 ×10-6/K to 11×10-6/K as temperature elevated from 50 ℃ to 400 ℃,thermal conductivity is 119.5 W/（m·K）.Bending strength of the alloy is 132 MPa and main fracture mode is brittle fracture of Si phase.The properties of the Al-65vol%Si alloy satisfy the need of electronic packaging.