烧结温度对铁基粉末冶金航空刹车材料组织的影响  

Effect of sintering temperature on contexture and performance of iron-based P/M aircraft brake materials

作　　者：姚萍屏[1] 张忠义[1] 汪琳[1] 熊翔[1] 何俊[1] 李红梅[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2007年第3期160-166,共7页Materials Science and Engineering of Powder Metallurgy

基　　金：中小企业创新基金资助项目(04C26114301310)

摘　　要：铁基粉末冶金刹车材料是飞机上常用的一种刹车材料,通常采用加压烧结工艺制得,在烧结工艺中,烧结温度是最为关键的参数之一。该文作者研究了烧结温度(900,930,950,980和1020℃)对其显微组织、致密化的影响以及由此引起的力学性能(硬度、抗压强度和抗弯强度)的变化。借助于材料组织结构及理论分析,阐述了该材料组织结构、力学性能变化的原因。研究表明:在烧结温度由900℃增至930℃的过程中,铁由体心立方结构的α-Fe全部转变为面心立方的γ-Fe,碳在γ-Fe中的扩散系数比其在α-Fe中的扩散系数低,使铁、碳合金化程度降低,然而,原子间互扩散系数增加,以及碳在γ-Fe中的溶解度比在α-Fe中的溶解度增大,使烧结得以进行,它们的综合作用则使材料密度、硬度和强度缓慢增加;继续提高烧结温度至1020℃,由于烧结温度、烧结压力及由二者引起的塑性变形作用使材料密度升高,同时,随烧结温度的升高,奥氏体均匀化程度提高,组织中生成了片间距不等、数量更多的珠光体,提高了材料的硬度及强度。The brake materials based on iron are usually made by P/M pressure sintering technique, which are often applied to braking apparatus of aircraft. Among the whole parameters, which affect sintering technology, the sintering temperature is a key one. The effect of different sintering temperatures on the microstructure, densification and mechanical properties of the tron-based P/M brake material were studiedand its mechanisms have been discussed in the presence of observation and analysis of microstructure and properties of the materials with different sintering temperatures. The result shows that with the increase of sintering temperature from 900 ℃ to 930 ℃, α-Fe of body-centered cubic lattice changed to γ-Fe of face-centered cubic lattice, the diffuse coefficient of C decreased, thereby, the alloying degree decreased between Fe and C. But the increase of mutual diffusion coefficient in different atoms and the solubility of C in Feled the sintering process to speed up. So, with the decrease of sintered property of iron powders and increase of mutual diffusion coefficient between different atoms, the density increased slowly. Since the comprehensive functions of sintering temperatures, sintering pressures and plastic deformations, a slowly accretion in density occurred and more number ofpearlites were observed by raising the sintering temperature from 930 ℃ to 1 020 ℃. Meanwhile, with the increase of sintering temperature, the degree of homogenization of austenite was increased, and the higher strength and hardness of the materials were reached.

关 键 词：粉末冶金刹车材料 烧结温度 力学性能 铁基 

分 类 号：TF125.9[冶金工程—粉末冶金]