摘要
研究Q235钢表面等离子W-Mo-Y共渗层的组织、成分、结构、显微硬度,计算渗层中不同位置、浓度下的W、Mo原子扩散系数。结果表明:渗层组织为柱状晶,W、Mo元素呈梯度分布,Y的分布不均匀。共渗层主要结构相为钨钼在α-Fe中的固溶体和Fe17Y2,共渗层显微硬度最高256 HV0.05;Y元素降低表面W、Mo的活度,W、Mo合金元素的化学势变小,表面与基体之间的化学梯度减小,W、Mo原子扩散速率减慢;W-Mo-Y共渗层厚度要比W-Mo共渗层厚度薄;通过Fick第二扩散定律计算表明,在W-Mo-Y共渗和W-Mo共渗时,不同渗层中的W、Mo扩散系数有所不同,但属同一数量级即:10-13～10-14之间。
Microstructure,micro-hardness and composition of W-Mo-Y co-diffusion alloying layer formed on surface of carbon steel by using glow plasma surface alloying technique were studied.The diffusion coefficients of W and Mo atoms at different position and concentration in the layer were calculated by Fick＇s second law.The results show that the microstructure of co-diffusion layer is columnar crystal.Element Y with uneven distribution mainly diffuses along grain boundary.The co-diffusion layer mainly consists of W and Mo solid solution in α-Fe and Fe17Y2.The highest hardness of the co-diffusion layer is 256HV0.05.Activity of W and Mo decreases as the element Y added,chemical potential of surface W and Mo elements becomes smaller and the chemical gradient between the alloying layer and matrix decreases and the diffusion rate of W and Mo atoms is reduced.The thickness of W-Mo-Y co-diffusion alloying layer is thinner than that of W-Mo co-diffusion layer.Calculated by Fick＇s second law,it is found that the diffusion coefficients of W and Mo atoms are different in different layers formed by W-Mo-Y co-diffusion alloying technique and W-Mo co-diffusion alloying technique,but the diffusion coefficients were in the same order of 10-13-10-14.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2011年第7期130-133,共4页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(50764002)
广西区基金重点项目(2010GXNSFD013008)
信息材料广西重点实验室主任研究项目(桂科能0710908-06-Z)
