超细晶粒Ti（C，N）基金属陶瓷刀具切削性能

利用真空烧结工艺制备了两组含有不同TiN成分的超细晶粒Ti(C,N)基金属陶瓷可转位刀片,用不同的切削速度和进给量切削正火45钢,分析了刀具的耐用度、磨损和失效方式等切削性能.结果表明:高速切削时刀具的磨损形式以氧化磨损和扩散磨损为主;在高速进给量大的切削条件下,含TiN低的刀片切削性能好于TiN高的刀片;切削速度对刀具寿命的影响很大;进给量在切削速度较低时对刀具寿命的影响程度要大于切削速度较高时.     

Ti(C,N)_w/Ti(C,N)基金属陶瓷的组织与力学性能研究

采用Ti(C,N)晶须和颗粒复合粉末(Ti(C,N)w+Ti(C,N)p)制备Ti(C,N)w/Ti(C,N)基金属陶瓷。研究了复合粉末对金属陶瓷组织及性能的影响。结果表明,Ti(C,N)w的加入,金属陶瓷的各项力学性能都得到了提高。组织表现为环形相结构特征,与Ti(C,N)基金属陶瓷相比,双层环形相结构所占比例增大,且尺寸加厚。烧结组织中Ti(C,N)w的长径比大于临界长径比,在强化金属陶瓷方面起着重要的作用。环形相使Ti(C,N)w与基体界面结合紧密,增韧机制主要表现为裂纹桥联和裂纹偏转,拔出效应不明显。     

Ti(C,N)基金属陶瓷的摩擦磨损研究

本文对Ti(C,N)基金属陶瓷材料的摩擦磨损行为及其磨损机理进行了研究.试验结果表明:与具有相同硬度的WC-Co合金和钢结硬质合金相比,Ti(C,N)金属陶瓷具有优异的耐磨性和较低的摩擦系数,其耐磨性随粘结相含量的增加而降低.Ti(C,N)基金属陶瓷磨损过程中,首先由表面微凸体间相互滑过,发生粘着,犁削,引起磨损,跑合一定时间后磨损由硬质相晶粒剥落控制.     

CO冷却对Ti(C,N)基金属陶瓷表层结构和切削性能的影响

为改善Ti(C,N)基金属陶瓷刀具的抗冲击性能,从烧结碳势对表层粘结相分布影响的角度出发,制备了不同压力CO冷却的Ti(C,N)基金属陶瓷刀片.借助扫描电镜和能谱仪研究了CO冷却下金属陶瓷表层的组织结构以及粘结相分布情况.对比了CO冷却和真空冷却对金属陶瓷刀片切削性能的影响.结果表明:CO冷却对金属陶瓷常规性能影响微小...     

Ti（C, N）基金属陶瓷刀具的高速切削性能与磨损机理

使用不同C与N摩尔比的Ti（C, N）固溶体粉末作为基体材料,采用真空烧结工艺研制两种Ti（C, N）基金属陶瓷刀片试样,并考察两种刀片试样和日本住友T1200A在不同的切削速度下干式车削20CrMn工件的切削性能。利用扫描电子显微镜分析刀具前、后刀面的磨损形态和显微结构,阐述Ti（C, N）基金属陶瓷刀具高速切削磨损机理。结果表明：高速切削时Ti（C, N）基金属陶瓷刀具的主要磨损形式是粘结、氧化和扩散磨损;减小Ti（C, N）固溶体中C与N的比值可改善Ti（C, N）基金属陶瓷刀具的耐磨性。     

Ti(C,N)基金属陶瓷添加成分的研究进展

简要介绍了Ti(C,N)基金属陶瓷的典型结构,着重概述了化学成分对Ti(C,N)基金属陶瓷组织和力学性能的影响。     

纳米Ti(C,N)基金属陶瓷制备技术研究进展

概述了纳米Ti(C,N)基金属陶瓷制备技术的研究进展,重点对纳米陶瓷粉末的团聚与分散、纳米陶瓷粉末的氧含量对性能的影响以及纳米金属陶瓷的烧结技术进行了介绍与探讨。分别介绍了真空烧结、放电等离子烧结、热压烧结以及微波烧结在制备纳米Ti(C,N)基金属陶瓷时的优势,及各自存在的问题,为开发新的适于纳米Ti(C,N)基金属陶瓷的烧结方法及烧结工艺提供了参考。     

渗硼对Ti(C,N)基金属陶瓷刀具性能的影响

采用粉末冶金法制备了Ti(C,N)基金属陶瓷,并用固体渗硼法对其进行了渗硼处理。研究了渗硼后金属陶瓷的微观组织和力学性能以及渗硼对切削性能的影响。结果表明:Ti(C,N)基金属陶瓷的渗硼层组织由硼化物层、扩散层和基体区组成。渗硼使金属陶瓷的表面硬度提高,抗弯强度降低。渗硼使金属陶瓷刀具在切削速度为200 m/min时的使用寿命提高约1倍;在300 m/min切削速度下,渗硼对延长金属陶瓷刀具的使用寿命没有明显作用;切削速度增至400 m/min时,渗硼使金属陶瓷刀具的使用寿命变短。强烈的热冲击是导致高速切削条件下渗硼层耐磨性降低的主要原因。渗硼层有效地减轻了金属陶瓷刀具表面发生的粘结,并抑制了刀具的扩散磨损和氧化磨损。     

Ti(C,N)基金属陶瓷抗弯强度的研究

研究了提高Ti(C,N)基金属陶瓷抗弯强度的方法。采用改变粘结相成分、进行低压烧结及快冷处理来制备Ti(C,N)基金属陶瓷。试验发现,粘结相成分对材料的强度有很大的影响,提高Ni/Ni+Co的比例可以提高材料的强度,当然,在实际应用中还要考虑对其它性能的综合影响;低压烧结和快冷处理都可以有效的提高Ti(C,N)基金属陶陶的抗弯强度。     

镍钴对超细Ti(C,N)基金属陶瓷性能的影响

研究了Co部分和全部代替Ni对超细Ti(C,N)基金属陶瓷性能的影响。采用X射线衍射仪对物相研究发现:金属相中w(Co)=10%和w(Co)=15%时,金属陶瓷中出现金属间化合物,并且有两种Co的同素异构体并存;力学性能测试表明:5%的Co取代5%的Ni可以明显提高金属陶瓷的抗弯强度、硬度和断裂韧性。金属相为10%Ni-5%Co时,材料的综合力学性能最好。     

Evolution of Ti （C, N）-based cermet microstructures

Two series of Ti(C, N)-based cermet materials originating from the same chemical composition but with dif-ferent grain size distribution and sintered to different stages of the sintering cycle have been studied using SEM, TEM,EDX, and XRD. Much of the surrounding structure is formed during solid state sintering. During the solid state sintering, at first, the Mo and W rich (Ti, Mo, W)C inner rim is formed by the interaction among TiC, WC, and Mo2C; then the Mo and W lean (Ti, Mo, W)(C, N)outer rim is formed. During the liquid phase sintering, the outer rim of coarse grains grows rapidly throw a solution-reprecipitation process; aLso coarse grains grow by particle coalescence. The interface between coarse grain outer rim and binder is flat (crystal surface).     

Microstructural evolution and characteristics during sintering of submicron Ti(C,N)-based cermet

1　INTRODUCTIONThebasiccompositionofTi(C ,N ) basedcer metsisTi(C ,N)andNi.IthasbeenknownthattheadditionofMoorMo2 Cisnecessarytoensuregoodwettability[1] ,andWCorothercarbidesareoftenaddedtoimprovetheplasticityofhardgrainsandhothardnessofthecermets[2 ] .Ti(C ,N) basedcermetsconsistmainlyofcarbonitride grainsandmetalbinder.The“core rim”structurewithinthehardgrainsisthetypicalmicrostructureofcermets .Thecarbonitride phaseenrichedMoandW (therimphase)hasbeenfoundtosurroundthe Ti(C ,…     

Effect of hot isostatic pressing nitrogen on the microstructure and properties of a Ti（C, N）-based cermet

The high-temperature, high-pressure hot isostatic pressing technology was used for depositing hard coatings on Ti（C, N）-based cermets. The rnicrostructure and properties of the sample were investigated using optical microscopy, scan- ning electron microscopy, X-ray diffraction, electron probe microanalysis, and microhardness tester. The results showed that the rich titanium and nitrogen in surface zone were induced by the heat treatment. The high nitrogen activity of the surface region was the driving force for outward transport of titanium and inward transport of tungsten in the cobalt binder. The toughness and hardness were improved and a hardness gradient was formed. It is the high-temperature, high-pressure N2 that enables closure of holes, thereby alleviating defects and prolonging tool life.     

渗硼对Ti(C,N)基金属陶瓷抗热震性能的影响

采用粉末冶金法制备了Ti(C,N)基金属陶瓷,并对其进行了固体渗硼。研究了渗硼后金属陶瓷的显微组织和力学性能以及渗硼对抗热震性能的影响。结果表明,Ti(C,N)基金属陶瓷的渗硼层由硼化物层、扩散层和基体区组成;渗硼使金属陶瓷的表面硬度提高,抗弯强度降低,使导致金属陶瓷热震残留强度急剧下降的临界热震温差降低约100℃;渗硼使Ti(C,N)基金属陶瓷热震后的残留强度降低,主要是分布不均和形状不规则的孔洞所致;当热震温差较小时,渗硼使金属陶瓷表面萌生热震裂纹的孕育期延长,从而推迟了主裂纹的形成;而热震温差较大时,经渗硼的金属陶瓷热震裂纹扩展较快,易形成龟裂。     

纳米Ti(C,N)增强Ti(C,N)基金属陶瓷的研究

采用纳米Ti(C，N)粉末制备Ti(C，N)基金属陶瓷，研究了纳米粉末对金属陶瓷组织及性能的影响。结果表明，粉末冶金过程中，纳米Ti(C，N)粉末易于在粘结相中扩散与溶解及沿晶界分布，降低了硬质相在粘结相中的溶解度，抑制了晶粒长大，提高了材料的红硬性能。抗弯强度与晶粒尺寸满足于Hall-Perch公式，5wt％～l0wt％的纳米粉末加入量可使金属陶瓷的抗弯强度和切削性能得到较大的提高，但硬度变化不大。切削磨损主要表现为磨粒磨损和轻微的粘着磨损，磨痕细小均匀。     

Effect of WC and group IV carbides on the cutting performance of Ti(C,N) cermet tools

The effect of carbides and nitrides from group IV (ZrC, ZrN and HfC) in the periodic table on the microstructure and cutting performance of Ti(C,N)–xWC–Ni systems was examined. The WC content was varied from 5 to 20 wt.% and additive carbides or nitrides were added individually at a level of 1 wt.%. In general, inserts containing 15 wt.% WC exhibited the longest tool life for turning while those containing 20 wt.% WC showed the longest tool life for milling. When 1 wt.% ZrC, ZrN, or HfC were added to Ti(C,N)–14WC–Ni (wt.%), these cermets showed the best cutting performance among the various cermet compositions investigated in this study. The improved performance can be attributed to the low strain energy developed between the core and rim interfaces.     

Microstructure and shear strength of the brazed joint of Ti（C,N）-based cermet to steel

Firm joins were obtained between Ti(C,N)-based cermet and steel with Ag-Cu-Zn-Ni filler metal by vacuum brazing. The effects of technological parameters such as brazing temperature, holding time, and filler thickness on the shear strength of the joints were investigated. The microstructure of welded area and the reaction products of the filler metal were examined by scanning electron microscopy (SEM), metallographic microscope (OM), energy-dispersive X-ray analysis (EDS), and X-ray diffraction (XRD). The brazing temperature of 870°C, holding time of 15 min, and filler thickness of 0.4 mm are a set of optimum technological parameters, under which the maximum shear strength of the joints, 176.5 MPa, is achieved. The results of microstructure show that the wettability of the filler metal on Ti(C,N)-based cermet and steel is well. A mutual solution layer and a diffusion layer exist between the welding base materials and the filler metal.