張維玉， 徐 駿， 石力開
( 北京有色金屬研究總院 國家有色金屬復合材料工程技術
研究中心, 北京 100088)
摘 要: 采用粉末冶金法制備了d 300 mm的15%SiCp/Al（體積分數）復合材料坯錠， 研究了擠壓態(tài)和T4態(tài)復合材料的力學性能和斷裂特點，揭示了基體強度和顆粒開裂對復合材料強度與塑性的影響規(guī)律。 結果表明： 復合材料T4態(tài)拉伸強度保持在560 MPa的水平下， 延伸率仍高達7%以上； 與擠壓態(tài)相比， T4態(tài)復合材料拉伸強度和屈服強度分別提高了68.5%和105%， 但塑性保持在同一水平。 斷口觀察表明： 擠壓態(tài)復合材料以基體斷裂為主， 而T4態(tài)復合材料除了基體斷裂外，還存在SiC顆粒開裂現象； 基體強度嚴重影響復合材料的斷裂形式， 顆粒開裂有利于提高復合材料的塑性。
關鍵字: SiCp/Al復合材料； 強度； 塑性； 基體強度； 顆粒開裂
ductility of SiCp/Al composites
ZHANG Wei-yu， XU Jun， SHI Li-kai
（National Engineering and Technology Research Center for
Nonferrous Metals Composites, Beijing General Research Institute for
Nonferrous Metals, Beijing 100088, China）
Abstract: 15%SiCp/Al composite billets with a diameter of 300 mm were fabricated by powder metallurgy method. Mechanical properties and fracture mechanisms of these composites as the extruded and in the T4 condition were investigated respectively. The effect of the matrix strength and particle fracture on the strength and ductility of the composites were presented. The results indicate that the composites in T4 condition gave an ultimate tensile strength of 560 MPa and elongation above 7%. 68.5% increase in ultimate tensile strength and 105% increase in yield strength are obtained in the composites in the T4 condition compared to as-extruded, whereas the elongation and reduction in area of the composites in the T4 condition remain at the same level in comparison with the as-extruded. Fractographic analysis reveals that the failure in the matrix near the interface is predominant in the as-extruded composites, with a preference for failure in the matrix and fracture of SiC particles in the T4 condition. It is shown that the dominant failure mode of the composites are significantly affected by the matrix strength. The particle fracture is beneficial to the improvement of ductility of the composites.
Key words: SiCp/Al composites; tensile strength; ductility; matrix strength; particle fracture
