电子封装用Si-Al系列合金组织与性能研究

【作者】 杨军；

【导师】 余琨；

【作者基本信息】 中南大学 ， 材料学， 2010， 硕士

【摘要】 本论文采用熔炼铸造和粉末热压的方法制备了Si质量分数为13%、27%、33%、50%、60%、70%、90%的一系列Si-Al合金,利用扫描电镜(SEM)、光学金相显微镜(OM)、差热分析(DSC)等分析手段和和多种检测方法,分析了Si-Al系列合金的力学性能、热物理性能,评价了Si-Al系列合金的应用性能,研究了Si-Al系列合金的显微形貌和成形机理,研究结果表明：1.Si-Al系列合金的三点抗弯强度,随着Si相含量的增加,呈现先增加后减小的趋势。Al相为连续相时,随着Si含量增加,合金的抗弯强度增加；Si相为连续相时,形成的骨架使合金的脆性增大,导致合金抗弯强度减小。2.Si-Al系列合金的热导率,随着Si相含量的增加,呈现逐渐减小的趋势。随着Si相含量的增加,电导率逐渐减小。3.Si-Al系列合金的热膨胀率,随着Si相含量的增加而减小,随着温度的升高而增大。在温度较低时,热膨胀率的增大速率较大,随着温度的升高,增加的速率逐渐减慢,温度到达300℃以上时,热膨胀率的增大速率已经很小。4.Si-Al合金金属化镀镍后,镀镍层与样品基体之间结合紧密,镀镍层厚度约为5μm。5.熔炼铸造法制备的13%、27%、33%Si-Al合金,熔体过热处理改善了Si-Al合金的凝固组织。当过热温度为850℃时,13%Si-Al合金的组织中同时存在初晶Si颗粒,共晶和α(Al)枝晶,当过热温度达到1000℃时,初晶Si相得到显著细化,共晶基体的针状硅细小,α(Al)枝晶完全消失。27%、33%Si-Al合金经过熔体过热处理,初生硅相数量和尺寸及共晶硅形貌发生了变化,初晶硅呈现五瓣星形状。6.粉末冶金法制备的50%、60%、70%、90%Si-Al合金的组织,都由硅相和富铝相组成。50%和60%Si-Al合金的铝相为连通相,硅相弥散分布其中。前者的硅相与原始硅粉末的形态、大小基本吻合,后者的硅相呈现扁平颗粒状,并有明显的方向性。70%和90%Si-Al合金的硅相已经练成骨架,铝相弥散分布其中,90%Si-Al合金的组织中有少量的闭合气孔存在。更多还原

【Abstract】 In this work, the Si-Al alloys with the mass fraction of 13%,27%,33%, 50%,60%,70%,90% Si content were prepared by casting and powder metallic methods. The experiments had been done by using scanning electron microscopy (SEM), optical metallographic microscope (OM) and differential thermal analysis (DSC). The mechanical performance, thermophysical performance and apply performance of Si-Al alloys were studied. and the relationship between morphology and deformation mechanism of Si-Al series alloys were analyzed. The results showed that:1. Si-Al series alloy three-point bending strength, with the Si phase content increases, showing the trend of increased and then decreased. Al phase, when the continuous phase, With the high-strength Si-phase increase, the bending strength of alloy increases; Si phase as continuous phase, the formation of the skeleton increases the brittleness of the alloy, resulting in reduced bending strength.2. Si-Al series alloy thermal conductivity, with the Si content increases, showing a gradual decrease trend. With the Si phase content increases, the conductivity decreases.3. The coefficient of thermal expansion(CTE) of Si-Al series alloy, With the Si phase content increases, showing the trend decreases, and increases with increasing temperature. At lower temperatures, the increase of thermal expansion is faste, as the temperature rises, the rate of increase gradually slow down, the temperature reaches above 300℃, the increase of thermal expansion is very small.4. Si-Al alloy after plating, binding between the coating and the matrix are close, coating thickness of about 5μm.5. Melt overheating can improve the Si-Al alloy solidification structure. When the temperature is 800℃13% Si-Al alloy, co-exsit primary Si particles, eutectic andα(Al) dendrite. when dealing with temperature reaches 1000℃，the primary Si phase has been significantly refined, eutectic silicon is small needle-like,α(Al) dendrites disappeared completely.27%,33% Si-Al alloy after hot melt processing, the number and size of primary Si phase and morphology of eutectic silicon changes, the shape of silicon presents five stars.6. The microstructures of 50%,60%,70% and 90% Si-Al alloy by powder metallic methods are composed by Si phase and Al-rich phase. Al phase is connect phase in 50%,60% Si-Al alloy. The shapes and sizes of Si phases in 50% Si-Al alloy are basically consistent with the original silicon powder, and in 60% Si-Al alloy show flat granular and power like. The Si phases in 70%,90% Si-Al alloy have been connected into a skeleton, and the microstructures of 90% Si-Al alloy have a small amount of closed pores更多还原