硬质合金相图热力学和扩散动力学数据库及其应用  

Thermodynamic and Diffusion Databases for Multicomponent Cemented Carbides and Their Applications

作　　者：张聪[1,2] 张伟彬[1,2] 彭英彪[1,2] 陈伟民[1,2] 周鹏[1,2] 陈利[1,2] 张利军[1,2] 刘树红[1,2] 杜勇[1,2] 王社权 

机构地区：[1]中南大学粉末冶金国家重点实验室,湖南长沙410083 [2]中德微结构联合实验室,湖南长沙410083 [3]株洲钻石切削刀具股份有限公司,湖南株洲412007

出　　处：《中国材料进展》2015年第1期1-14,63,共15页Materials China

基　　金：国家自然科学基金资助项目(51371199;51474239;51371201);工业信息化部"高档数控机床与基础制造装备"科技重大专项(2015ZX04005008);中德科学中心资助项目(GZ755);科技部"973"计划项目(2011CB610401;2014CB644002);中南大学"升华学者"特聘教授启动基金;中南大学中央高校基本科研业务费专项资金(2014zzts022)

摘　　要：硬质合金是由难熔金属化合物和粘结相通过粉末冶金工艺制成的材料,它具有硬度高、耐磨、强度和韧性好、耐热、耐腐蚀等一系列优良性能。介绍了包含C-Co-Cr-W-Ta-Ti-Nb-N等元素的硬质合金热力学和动力学数据库。简述了热力学数据库中的热力学模型和优化计算,并以C-Cr-Ta三元系为例介绍了热力学优化计算的方法和步骤。所建立的硬质合金动力学数据库包含液相和fcc相不同元素的原子迁移参数。利用修正的Sutherland方程对液相的原子迁移参数进行了评估,而fcc相原子迁移参数是基于对实验测定数据和文献数据的评估获得的。利用建立的硬质合金热力学和动力学数据库,可以计算多元系的相平衡、获取不同相的热力学性质和溶解度信息、模拟合金中元素和相的分布等。该数据库可用于设计合金成分和烧结温度、预测元素含量及烧结气氛等对梯度硬质合金形成的影响、优化合金烧结工艺等。最后指出相图热力学和扩散动力学数据库及热物性数据库结合相场、有限元方法,定量描述硬质合金结构-性能的关系是今后的发展趋势。Cemented carbides, which consist of refractory compounds and binder phase, are produced through powder metallurgy process. They show high hardness, wear resistance, strength with good toughness, heat resistance, corrosion resistance and a series of excellent performance. This paper presents developed thermodynamic and diffusion databases for muhicomponent cemented carbides. The databases cover the system C-Co-Cr-W-Ta-Ti-Nb-N. The thermodynamic models and assessments are briefly introduced. The C-Cr-Ta ternary system is shown as an example to describe the procedure of thermodynamic assessment. The diffusion database contains atomic mobility parameters for different diffusing elements in liquid and fcc phases. The atomic mobility parameters in liquid phase are theoretically calculated by the modified Suther- land equation, and atomic mobility parameters in fcc phase are optimized according to the presently measured diffusivi- ties and the literature data. The developed thermodynamic and diffusion databases can be used to calculate phase equi- libria in muhicomponent alloys, simulate the distribution of elements and phases in alloys. Consequently, the databases are suitable for realizing applications as controlling the alloy composition and sintering temperature, predicting the effect of elements content and sintering atmosphere on the formation of graded cemented carbides, designing and optimizing sintering process for cemented carbides. It is expected that a quantitative description of the relationship between the structure and performance through a combination of thermodynamic, diffusion and thermophysical databases with phase field model and finite element method is the main focus for the future development of cemented carbides.

关 键 词：硬质合金 热力学 动力学 数据库 计算模拟 应用 

分 类 号：TG135.5[一般工业技术—材料科学与工程]