斯松华
,
于婉萍
,
张磊
,
李飞
机械工程材料
doi:10.11973/jxgccl201508021
采用等离子堆焊技术在低碳钢表面分别制备了Co40合金堆焊层以及分别添加30％(质量分数)微米和纳米Cr3C2的Co40合金(Cr3C2/Co)复合堆焊层,对比研究了添加微米和纳米Cr3C2对Co40合金堆焊层组织与磨损性能的影响.结果表明:Co40合金堆焊层的组织主要为发达柱状晶及其间的网状共晶;微米Cr3C2/Co复合堆焊层中的柱状晶明显被打断、碎化,生长方向性减弱,且其组织更加均匀和细小;纳米Cr3C2/Co复合堆焊层的结晶方式则由亚共晶转变为共晶,其组织主要由共晶组织组成,且进一步细化和均匀化;与Co40合金堆焊层相比,微米CrC/Co复合堆焊层的硬度和耐磨性分别提高了37％和29％,而纳米CrC2/Co复合堆焊层的硬度和耐磨性则分别提高了50％和55％.
关键词:
等离子堆焊
,
Co40合金
,
纳米Cr3C2
,
组织
,
耐磨性
斯松华
,
于婉萍
,
姚昌彬
,
张磊
机械工程材料
doi:10.11973/jxgccl201701016
采用等离子堆焊技术在 Q890低碳钢表面制备了不同纳米 Cr3 C2颗粒含量(质量分数分别为0,20％,30％,40％)的Co40合金层,研究了纳米Cr3 C2颗粒含量对该合金层组织与耐磨性的影响.结果表明：Co40合金层主要由发达柱状晶及其间的网状共晶组成；添加纳米 Cr3 C2颗粒后其组织发生细化,结晶方式由亚共晶结晶转变为过共晶结晶且合金层的硬度和耐磨性均得到了明显提高；当纳米Cr3 C2颗粒为30％时,合金层的磨损质量损失最小,比未添加 Cr3 C2的减少了55．8％,磨损表面较平整,只存在轻微的犁沟,几乎没有剥落现象.
关键词:
等离子堆焊
,
Co40 合金层
,
纳米Cr3 C2 颗粒
,
显微组织
,
耐磨性
L.J.Shang
金属学报(英文版)
A gradient coating of Fe-based alloy was manufactured with rare earths (RE) by plasma surfacing on Q235 steel substrate. The coatings were studied by using X-ray diffraction (XRD), scanning electron microscope (SEM), differential thermal analyzer (DTA), and electron probe micro-analyzer (EPMA). The results show that the phases of the two kinds of coatings(with and without RE) both include α-Fe, Fe7C3， Fe3C, Cr2B, Fe2B and FeB. The microstructure of F314 coating is mainly hypereutectic, the pro-phases Cr7C3 and Cr2B are loose, crassi, spiculate and contain microcracks. The brittleness of the coating is high, and the average hardness is 787 HV. When 0.8wtRE was added into the F314 alloy, the microstructure varied from hypoeutectic to hypereutectic continuously, The hardness appears as gradient distribution with the highest value of 773 HV, meanwhile, the brittleness decreases significantly. The formation of gradient structure depends on the fallowing factors: (i) the conversion of RE. The addition of RE lowers the elements point and Fe-C eutectic temperature, thus the base metal melting acutely. (ii) the heating of plasma arc.Graded temperature results in directional solidification, thus the gradient structure forms easily. The main reasons for the hardness decrease with RE addition in the alloy are the ratio of hard phase lowering and the hardness of the hard phase decreasing.
关键词:
rate earth
,
null
,
null
