以粉末燒結及擠製法製作Cu/SiCp複合材料

Abstract

以粉末燒結法配合擠製成型法，在銅中混入SiC粉末形成Cu/SiC 金屬基複合材料，對於銅的機械性質可有明顯之提升。因為SiC粉末 能 在銅基材中形成散佈強化的效果，而SiC粉末與銅基材之間鍵結良 否與 散佈均勻度為達到散佈強化之主要關鍵，經由無電電鍍銅法在 SiC粉末 表面上鍍上一層銅薄膜予以活化，可使SiC粉末與銅基材間 有良好的鍵 結。 本研究詳細探討SiC含量對以粉末燒結及擠製成型所製造之 Cu/SiC複合材料性質之影響，如密度、硬度、最大拉伸強度、表面 電阻 及放電加工等均予以測量，並比較所含之SiC粉末有無鍍銅對材 料性質 之影響，及其形成之微結構與破壞機構，所有情況皆顯示含已 鍍銅SiC 粉末之複合材料性質比含未鍍銅者為佳。例如經燒結後之擠 製品之硬度 ，在SiC含量10wt％時，前者較後者高出13％，更優於 純銅粉之成品45 ％。 由本實驗之各項結果，可以確定經過擠製成型法可以大幅提升 單 以粉末燒結法所得之材料特性，甚至可以免除在擠製前之燒結過程。 The mechanical properties of Cu/SiC metal-matrix composite (MMC), made by powder sintering and extrusion, can be improved evidently compared with that of the pure copper counterpart. This is due to the dispersed strengthening effect of SiC powder dispersed in Cu matrix. The conditions of the bonding between SiC powder and copper matrix and the dispersion uniformity are the governing factors. It was found that an improved bonding can be achieved by activation of SiC powder surface through electroless- coating of Cu onto SiC powder. The studies investigate the effect of the amount of SiC on the properties of Cu/SiC composite made by powder sintering and extrusion; for example, density, hardness, ultimate strength, surface electrical resistance and electrical discharge machining properties were measured. Especially, the effects of Cu-coating SiC powder on the properties of material, the microstructures and the fracture mechanisms were studied in detail. All results showed that the properties of composites employing Cu-coated SiC powder are better than those of uncoated SiC powder. For example, in case of Cu- 10wt% SiC, the hardness of the coated was 13% higher than that of the uncoated, and 45% higher than the pure Cu counterpart after the same sintering and extrusion condition. From results of the present work, it is apparent that the properties of the compostie made through powder sintering can be increased further after extrusion; in most cases, the powder sintering process can even be deleted leaving powder extrusion alone to achieve similar composite properties.