烧结亚共晶高铬铸铁制备及其显微组织与性能  

Sintering Fabrication of a Hypoeutectic High Chromium Cast Iron as well as Its Microstructure and Properties

作　　者：肖平安[1] 宋建勇[1] 陈超[1] 刘洋[1] 李志华[1] 顾景洪 

机构地区：[1]湖南大学材料科学与工程学院,湖南长沙410082

出　　处：《湖南大学学报（自然科学版）》2017年第6期37-44,共8页Journal of Hunan University:Natural Sciences

基　　金：国家自然科学基金资助项目(51574119)~~

摘　　要：以水雾化高铬铸铁粉末为原料,通过压制/烧结工艺制备了一种亚共晶高铬铸铁(SHCCI),对其显微组织、物理力学性能和冲击磨粒磨损工况下的耐磨性能开展了系统的观察、分析与检测,并与成分相近的传统铸造高铬铸铁(CHCCI)进行了对比研究.试验结果表明,通过超固相线液相烧结可以制备出密度达到7.44g/cm^3的亚共晶高铬铸铁,其Cr_7C_3型碳化物呈细小短杆状,沿晶界均匀地分布在由马氏体和奥氏体混合组成的基体中;烧结态高铬铸铁的硬度为HRC58,抗弯强度为2 122MPa,冲击韧性达到6.5J/cm^2(无缺口试样尺寸为5mm×5mm×50mm);与铸造高铬铸铁相比,由于碳化物形貌、大小和分布均匀性的明显改善,以及基体中有更多的马氏体,烧结高铬铸铁在各种冲击载荷下均展现出明显的抗磨粒磨损性能优势,是一种十分优异的耐磨材料.A sintered hypoeutectic high chromium cast iron （SHCCI） was fabricated by a powder met- allurgy process with water atomized powders as raw materials. Its microstructure, mechanical properties and impact abrasion resistance were systematically analyzed or/and detected, and compared with an as-cast high chromium cast iron （CHCCI） with the same composition. The results showed that the density of SHCCI could be of 7.44 g/cm3 as supersolidus liquid phase sintering was applied. There was only CrTC3- type carbides in SHCCI,and its matrix with fine grain size was a hybrid of a major part of martensite and austensite. The short rod shape Cr7 C3 carbides were homogeneously dispersed along grain or subgrain boundaries. The hardness, bending strength and impact toughness（specimens with dimensions of 5 mmX 5 mm X 50 mm were used）of the as-sintered SHCCI were of HRC58,2 122 MPa and 6.5 J/cm2, respectively. With the dramatical improvement of morphology,size and distribution of carbides as well as more amount of martensite in the matrix, as-sintered SHCCI presented evident advantages of impact abrasive resistance under all kinds of impact charges over CHCCI.

关 键 词：粉末冶金 高铬铸铁 碳化物 冲击磨料磨损 

分 类 号：TF124[冶金工程—粉末冶金]