基体对涂层硬质合金组织和性能的影响

【作者】 王社权；

【导师】 陈康华； 李来荣；

【作者基本信息】 中南大学 ， 材料学， 2003， 硕士

【摘要】 目前，涂层硬质合金可转位刀片使用越来越广泛，不同的使用领域对涂层合金提出不同的要求。但要获得性能优良的涂层硬质合金，必须要有性能优良的专用硬质合金基体与涂层相配合。 本文采用4种成分不同的硬质合金基体，WC-Co、WC-(W,Ti)C-(Ta,Nb)C-6％Co、WC-(W,Ti)C-(Ta,Nb)C-10％Co、WC-(W,Ti)C-(Wa,Nb)C-TiCN-Co。通过常规的检测、金相显微镜、扫描电镜及能谱分析、切削实验等一些手段，研究了碳含量和烧结气氛对硬质合金基体性能的影响，TiCN含量对WC-(W,Ti)C-(Ta,Nb)C-TiCN-Co合金性能的影响，涂层硬质合金的界面结构及切削性能，涂层硬质合金在不同应用条件下切削性能的优缺点。本研究的结果表明： 1．WC-(W,Ti)C-(Ta,Nb)C-TiCN-Co基体由于含有脱β层，综合性能十分优越。抗弯强度比WC-Co、WC-(W,Ti)C-(Ta,Nb)C-6％Co合金高，硬度与WC-(W,Ti)C-(Ta,Nb)-6％Co合金相当。 2．基体的性能受碳含量和烧结气氛的影响，随着合金碳含量的增加，合金的抗弯强度和硬度依次下降。在Ar气下烧结，WC-(W,Ti)C-(Ta,Nb)C-6％～10％Co合金由于有(W,Ti)C和(Ta,Nb)C固溶体的存在，表面有Co相聚集。 3．合金基体进行涂层后，合金的抗弯强度大幅下降。基体配碳量低，在基体和涂层之间形成脱碳相。 4．WC-Co基体涂层合金适合于加工铸铁，低Co含量的WC-(W,Ti)C-(Ta,Nb)C-Co合金适合于加工钢材，高Co含量的WC-(W,Ti)C-(Ta,Nb)C-Co合金在切削实验条件下基本无明显的优势。表面富Co层(脱β层)合金由于刃口强度高，综合使用性能良好。更多还原

【Abstract】 The coated cemented carbide indexable inserts are used more and more widely. The different application requires the coated cemented carbides with corresponding property. High performance coated cemented carbide should be based on special cemented carbide substrate.Four cemented carbide WC-Co,WC-(W,Ti)C-(Ta,Nb)C-6%Co, WC-(W,Ti)C-(Ta,Nb)C-10%Co, WC-(W,Ti)C-(Ta,Nb)C-TiCN-Co have been processed and investigated as the substrates for coating. By conventional inspection, microscope, SEM, the effect of carbon content and sintering atmosphere as well as TiCN content on the properties and interface structure of the coated cemented carbide substrate were studied. The cutting performance of coated cemented carbides were examined by metal cutting test.WC-(W,Ti)C-(Ta,Nb)C-TiCN-Co alloy as substrate has excellent properties with higher TRS than alloys of WC-Co, WC-(W,Ti) C-(Ta,Nb)- 6%Co, with the same hardness as WC-(W,Ti)C-(Ta,Nb)C -6%Coo There are enriched cobalt layer in the surface of WC-(W,Ti) C-(Ta,Nb)C-TiCN-Co alloy , which is beneficial to coating as substrate.TRS and hardness of cemented carbide as substrate decrease with the increase of alloy carbon content which depends on the initial carbon content and sintering atmosphere. Sintering in Argon results in formation of (W,Ti) C and (Ta,Nb) C in alloys of WC-(W,Ti) C-(Ta,Nb)-6%Co and WC-(W,Ti)C-(Ta,Nb)C-10%Co, and cobalt segregation on the surface of alloys.After coated, TRS of the cemented carbide deteriorates obviously, N-phase appears in the interface between substrate and coat in the case of the low carbon content.The cutting experioments show that the coated WC-Co is suitable for cutting cast iron, the coated WC-TiC-(Ta, Nb)C-6%Co suitable for steel, the coated WC-(W,Ti) C-(Ta,Nb) C-TiCN-Co with high strength edge is the best. The WC-TiC-(Ta,Nb)C -10%Co can not be used as substrate.更多还原