论文部分内容阅读
研究了1100℃烧结温度下合金元素铜、镍含量对铸铁短纤维烧结特性的影响规律,结果表明:与铁—铜粉末压坯相比,铸铁短纤维—铜压坯烧结后的最大膨胀率及相对应的铜含量均明显减少。产生膨胀的主要原因是铜熔化后,富铜液相向奥氏体中扩散,在原位留下空隙,而液相沿界面流动不明显。镍显著加快了铸铁短纤维烧结体的致密化。在镍含量高于4.5％时,显微组织中出现奥氏体相,在奥氏体与珠光体边界析出网状渗碳体,在奥氏体晶内析出魏氏碳化物及游离石墨,引起致密化速率下降,断裂方式由延性断裂转化为脆性断裂。
The effect of copper and nickel content on the sintering properties of cast iron short fiber was investigated at 1100 ℃ sintering temperature. The results show that the maximum expansion rate of cast iron short fiber-copper compact after sintering is lower than that of iron- The corresponding copper content was significantly reduced. The main reason for the expansion is that after the copper is melted, the copper-rich liquid phase diffuses into the austenite and leaves voids in place, while the liquid phase does not flow significantly along the interface. Nickel significantly accelerates the densification of cast iron short fiber sintered bodies. When the nickel content is higher than 4.5%, the austenite phase appears in the microstructure, reticular cementite is precipitated at the boundary between austenite and pearlite, and Wei’s carbide and free graphite are precipitated in the austenite grain, causing The densification rate decreases and the fracture mode changes from ductile fracture to brittle fracture.