Cr_7C_3/Ni_3Al复合材料制备过程中碳化铬的溶解再析出行为  

SOLUTION AND PRECIPITATION OF CHROMIUM CARBIDE DURING THE FABRICATED PROCESS OF Cr_7C_3/Ni_3Al COMPOSITE

作　　者：李尚平[1] 冯涤[1] 骆合力[1] 刘君秋[1] 

机构地区：[1]钢铁研究总院高温材料研究所,北京100081

出　　处：《复合材料学报》2005年第4期53-57,共5页Acta Materiae Compositae Sinica

基　　金：国家高技术研究发展计划项目(2002AA331070)

摘　　要：将真空常压烧结方法制得的Cr3C2-Ni-Al复合焊丝堆焊于碳钢表面。分析表明,在堆焊过程中,利用氩弧物理热和Ni-Al反应热,Ni与Al化合反应生成Ni3Al金属间化合物,Cr3C2则发生分解,除少部分[C]与[Cr]固溶于Ni3Al基体中外,大部分反应析出更稳定的Cr7C3相,其尺寸取决于堆焊层中不同区域的冷却环境,较为均匀地分布于Ni3Al基体中。由于Cr在Ni3Al中的固溶度远大于C,加之Cr3C2转化为Cr7C3也造成部分富余的C,结果造成在该Ni3Al表面强化材料焊层中形成石墨相,其密度轻、熔点高,主要偏聚于焊层表层。Cr7C3/Ni3Al复合材料的室温、高温硬度远高于传统高温耐磨材料Stellite合金,该材料有望成为一种新型的高温耐磨表面强化材料。A Cr3Cz-Ni-Al welding wire was produced by pressureless sintering process in vacuum. When the welding wires were welded on the surface of carbon steel, carbide particles reinforced Ni3Al base composite was formed due to the physical heat of arc and Ni-Al exothermic reaction. XRD shows that Ni reacts with Al to form Ni3Al and Cr3C2 is dissolved during welding. Most of [Cr] and [C] react to form Cr2C3 phase except that a few dissolve into Ni3Al matrix. The size of Cr7C3 particles mainly depends on the cooling rate of different welding regions.In addition, as the solid solubility of Cr in Ni3Al is much larger than that of C and Cr3C2 changes to Cr7C3 during welding, some graphites are formed in welding layers. The graphites mainly segregate on welding outer layers due to its low density and high melting point. The room and high temperature hardness of Cr7C3/ Ni3Al composite ismuch higher than that of stellite alloys. It is predicted that Cr7C3/ Ni3Al composite may become an attractive potential candidate for high-temperature surface wear-resistant material.

关 键 词：NI3AL 碳化铬 高温耐磨 溶解 析出 

分 类 号：TB333[一般工业技术—材料科学与工程]