Structures And Properties Of Electronic Packaging Component Of SiC Particles Reinforced Aluminum Composite

In this study, reparation process of SiC/Al composites'slurry and the electronic packing parts'forming processes were studied, and the parts'macrostructure characteristic and microstructure were observed and researched, and the parts'mechanical properties and physical properties were tested and analyzed. It was found that, SiC/Al composites'slurry with good flow property and uniformity was fabricated successfully, and the electronic packing castings with the compact component and excellent comprehensive properties were formed in the centrifugal force field. The conclusions were as following:Two kinds of SiC/Al composites'slurry were fabricated successfully by semi-solid mechanical stirring method. In the two kinds of SiC/Al composites'slurry, ZL109 was adopt as matrix material, and the greenα-SiC particles were selected as reinforcement. Selected average sizes of the particles were 30μm, 79μm and 120μm, and, mass rations of these three average sizes were 1:2:3. The volume fraction of SiC particles was 22% in the first composites'slurry, while the value of the second composites'slurry was 27%. The results of experiments showed that, the temperature of adding the SiC particles was 560±5℃; the adding particles'speed in the first half hour was 30g/min, then with the particles added, the adding particles'speed was increased to 60g/min; the mixing speed was 370r/min at first, then it was up to 600r/min.In order to increase the volume fraction of SiC particles, a kind of heating coating was fabricated by my self. The results showed that the coating didn't achieve its intended goal. KNO3 of the coating liberated lot of gas in the high temperature, which wasn't entirely consumed. While some of them impeded the movement of SiC particles in the mold, which decreased the volume fraction of SiC particles in the particles-rich region. Some gas shouldn't spread into environment, so big gas bubble formed in the last solidification place of the casting.The tests were taken in the castings, which macrostructure characteristic, microstructure, the mechanical properties and physical properties were observed, tested and analyzed. The OM was used to observe the tests'microstructure. The volume fractions of SiC particles were tested in the means of density method and image analysis method. The HRB of the tests were tested. The tests'CET and TC were tested by the thermal expansion device and laser conductometer, respective. It was founded that, the SiC/Al composites were separated clearly in the centrifugal force field. There were three regions in the sections of casting: the particles-rich region, the alloy-rich region and the inclusions-rich region. Microstructure observation showed that, the microstructure of the component was very sound and compact, and the distributions of SiC particles were homogeneous. Through the tests of the volume fraction, the values at different locations were different. The value in the left-side was the biggest, and the values in the component bottom and the right-side were nearly same, which was smaller than that in the left-side, and the values in the lower hole-side was smaller than that in the right-side, and the values in the upper hole-side was the smallest. The HRB, CET and TC of the tests were founded the same laws.