硅对烧结态高铬铸铁组织与性能的影响研究  

Effect of Silicon on Microstructure and Properties of Sintered High Chromium Cast Iron

作　　者：石管华 肖平安[1] 顾景洪 李忠涛 肖利洋 SHI Guanhua;XIAO Pingan;GU Jinghong;LI Zhongtao;XIAO Liyang(College of Materials Science and Engineering,Hunan University,Changsha 410082,China)

机构地区：[1]湖南大学材料科学与工程学院

出　　处：《航空制造技术》2019年第22期52-57,72,共7页Aeronautical Manufacturing Technology

基　　金：国家自然科学基金(51574119)

摘　　要：以两种不同含高Si量的水雾化预合金粉末为原料,通过DSC分析确定烧结温度区间,采用超固相线液相烧结制备出高综合力学性能的高铬铸铁。采用光学显微镜和扫描电镜分析高铬铸铁显微组织的变化,并对两种成分的烧结态高铬铸铁性能进行对比分析。研究结果表明:其他成分相近的两种合金,Si质量分数为1.48%时合金为亚共晶成分,Si质量分数为3.23%时则表现为典型的过共晶成分。两者碳化物均呈短杆状,均匀分布在晶界和亚晶界处。同时Si原子可以固溶于奥氏体中,降低C、Cr原子在奥氏体中的溶解度,进而影响奥氏体稳定性,最终两种合金得到不同的基体组织。相较于Si质量分数为1.48%的合金,Si质量分数为3.23%的合金的力学性能均有所下降。其中Si质量分数为1.48%的合金硬度HRC56.5、冲击韧性9.59J/cm^2、抗弯强度2208.98MPa,Si质量分数为3.23%的合金硬度HRC48.5、冲击韧性2.73J/cm^2、抗弯强度1664.28MPa。Two kinds of water atomized pre-alloyed powders with high Si content were used as raw materials. The sintering temperature range was determined by DSC analysis. High chromium cast iron with high mechanical properties were prepared by super-solidus liquid phase sintering(SLPS). Optical microscopy and scanning electron microscopy were used to analyze the microstructure changes of high chromium cast iron, and the performance of two-component sintered high chromium cast iron was compared and analyzed. The results show that the alloys with similar composition, the alloy containing 1.48% of Si is hypoeutectic, and the alloy containing 3.23% of Si is a typical hypereutectic composition. Both carbides are short rods, evenly distributed at the grain boundary and the subgrain boundary. At the same time, Si atoms can be dissolved in austenite, which reduces the solubility of C and Cr atoms in austenite, which in turn affects the austenite stability. Finally, the two alloys get different matrix structures. Compared with the alloy containing 1.48% of Si, the mechanical properties of the alloy containing 3.23% of Si decreased. The hardness of the alloy containing 1.48% of Si is HRC56.5, the impact toughness is 9.59 J/cm^2, the bending strength is 2208.98 MPa. The hardness of the alloy containing 3.23% of Si is HRC48.5, the impact toughness is 2.73 J/cm^2 and the bending strength is 1664.28 MPa.

关 键 词：高铬铸铁 合金元素 碳化物 力学性能 超固相线液相烧结(SLPS) 

分 类 号：TG1[金属学及工艺—金属学]