高综合性能亚共晶高铬铸铁的烧结制备  

Sintered high performance hypoeutectic high chromium cast iron

作　　者：肖平安[1] 张霞[1] 范安平[1] 曹杰义 李晨坤[1] 

机构地区：[1]湖南大学材料科学与工程学院,长沙410082

出　　处：《粉末冶金材料科学与工程》2015年第1期78-85,共8页Materials Science and Engineering of Powder Metallurgy

基　　金：国家自然科学基金资助项目(51074070);湖南省自然科学基金资助项目(13JJ3043);新金属材料国家重点试验室开放基金资助项目(2012-206)

摘　　要：以气雾化粉末为原料,采用液相烧结(LPS)制备亚共晶高铬铸铁(HCCIs),系统研究烧结工艺参数对致密化行为、显微组织演变和力学性能的影响规律。研究结果表明,采用LPS可以获得相对致密度达99%以上的制品,但合适的烧结温度范围很窄;XRD分析表明烧结亚共晶高铬铸铁由M7C3型碳化物、马氏体和奥氏体构成;金相分析显示烧结样晶粒细小,碳化物为一次晶杆状,且分布均匀。随烧结温度升高和保温时间延长,晶粒和碳化物均逐步粗化,其中温度的影响更加显著;而强度和冲击韧性则呈现先升高后降低的变化规律。优化的烧结工艺下高铬铸铁的力学性能为:硬度HRC65,抗弯强度1 199 MPa,冲击韧性4.6 J/cm2。并提出了一个烧结高铬铸铁中碳化物形态演变的生长模型。The hypoeutectic high chromium cast irons（HCCIs） were fabricated by liquid phase sintering（LPS） technology using gas atomized powders as raw material. The effect of sintering parameters on densification, microstructure and mechanical properties was studied systematically. The results show that, the products of relative density up to 99% can be obtained by this method, but proper sintering temperature is very narrow. The X-ray diffraction（XRD） reveals that the hypoeutectic HCCIs holds the follow constituents in its matrix： M7C3 carbide, martensite and austenite, and metallographic analysis shows that the grains are fine, M7C3 carbides are crystal rod with uniform distribution. With increasing sintering temperature and holding time, both grain size and carbide are coarsen gradually, while the strength and toughness increase first and then decrease, in which the temperature has a more significant effect. Under the optimum conditions, the mechanical properties of sintered hypoeutectic HCCIs are： hardness HRC65, bending strength 1195 MPa, and impact toughness 4.6J/cm^2. A model about carbide morphology evolution of sintered hypoeutectic HCCIs has been proposed.

关 键 词：亚共晶高铬铸铁 超固相线液相烧结 显微组织 力学性能 生长模型 

分 类 号：TF124[冶金工程—粉末冶金]