超细晶粒WC硬质合金的研制动态

论述了超细晶粒WC硬质合金经历的从普通合金、亚微细晶粒合金到超细乃至纳米晶粒合金三大发展阶段,它们在金属加工、电子工业、木材加工、医学等领域的主要应用,以及有关的粉末原料和合金的最新研制动态     

VC/Cr3C2对微波烧结超细WC-10Co性能的影响

利用微波烧结技术，研究了添加VC／CBQ晶粒生长抑制剂对WC-10Co超细硬质合金微观结构及性能的影响。结果表明，添加总量质量分数为0．6％的抑制剂的合金的综合性能最好，过量的抑制剂反而会降低合金性能；并且微波烧结合金不论是否有晶粒长大抑制剂，均能得到均匀的细晶结构。     

冷等静压成形及烧结温度对超细WC-TiC-Co 硬质合金性能的影响

采用高能球磨法制备了平均粒度约为550nm的WC-5TiC-10Co超细粉体.研究了冷等静压成形及烧结温度对合金试样性能的影响.结果表明:超细粉体在280MPa、保压2min的冷等静压条件下,压坯密度达到8.13g/cm3且趋于恒定.相同烧结温度下,冷等静压试样的性能优于普通压制试样;随着烧结温度的升高,合金试样的密度提高,硬度和抗弯强度先升高后降低;最佳烧结温度在1450℃左右,试样的密度达到12.08g/cm3,洛氏硬度(HRA)值高达93.6,抗弯强度达到1224MPa.     

WC—Co硬质合金冲蚀磨损行为及机理研究

本文对两种WC—Co硬质合金的耐冲蚀性进行了考察,二者均呈现脆性材料冲蚀特点。其组成相的晶粒尺寸、硬度、百分含量与形貌对材料的冲蚀行为有巨大影响,在高温下尤为明显。材料的耐磨性随磨料硬度增加而降低。超细晶粒硬质合金具有更佳的耐磨性,但其磨蚀机理与商用硬质合金相似。软磨粒冲蚀引起软的Co相粘接剂浸蚀,导致WC相脱落。硬磨料冲蚀时,材料的转移主要是由于低角度时的切削和犁耕,高角度时的疲劳断裂组成,二者均伴有大面积的塑性变形。     

低温低压烧结WC-8Co硬质合金

采用低温低压烧结WC-8Co硬质合金,并研究了烧结温度和烧结压力对硬质合金组织和性能的影响.研究结果表明:随着烧结温度的升高,WC-8Co硬质合金的孔隙减少,晶粒尺寸和密度增大;硬质合金的硬度与抗弯强度随着密度的增大而提高.当烧结温度高于1 280℃时,WC-8Co硬质合金的烧结方式为液相烧结;烧结压力有利于硬质合金的致密化.当烧结温度为1 300℃,烧结压力为5 MPa时,WC-8Co硬质合金的密度、硬度和抗弯强度分别为14.61 g/cm3、90.7 HRA和1 830 MPa.     

WC-Co超细硬质合金的超声波无损检测

采用单探头直接接触纵波探伤的方法,检测了9根WC-10 Co硬质合金试样的超声波衰减系数α,结合试样的密度、晶粒度、断裂韧性KIc、维氏硬度及抗弯强度进行分析。结果表明:合金的晶粒度越小,超声波衰减系数α越大,断裂韧性越高,而超声波衰减系数与密度、硬度和抗弯强度没有直接的关系。可用超声波在WC-10 Co硬质合金中的衰减行为来评估材料的韧性,从而替代有损的机械方法。     

非均匀结构WC—Co硬质合金

对采用碳化烧结法制取非均匀结构硬质合金的工艺进行了研究。结果表明，碳化烧结工艺可制得非均匀结构ＷＣ－Ｃｏ硬质合金，配Ｃ量以６．０％￣６．１％（质量分数）较好，最佳烧结温度为１４２０￣１４５０℃。ＷＣ－１０％Ｃｏ（质量分数）合金的抗弯强度бｂｂ可达２６００￣２９００ＭＰａ，密度ｐ为１４．４￣１４．６ｇ／ｃｍ＾３，硬度ＨＲＡ为８８．２￣８９．９。此外，还可以获得ＷＣ〈１μｍ的合金。     

烧结工艺对破碎再生料硬质合金性能的影响

根据不同的烧结温度,对YG8破碎再生料进行不同的对照试验。采用湿磨、干燥、压制以及不同烧结温度的粉末冶金方法,得到不同烧结温度下的合金试样;对试样分别进行各项物理性能测定和金相观察,收集数据并进行分析。结果表明:在一定范围内,硬质合金破碎再生料的各项物理指标均随着烧结温度的升高而先升高后降低,并在烧结温度为1 410℃时综合性能达到最佳。     

Research on Ultrafine WC-lOCo Cemented Carbide with High Properties

WC- 10Co nanocomposite powder produced by spray pyrolysis-continuoas reduction and carbonization technology was used, and the vacuum sinteriag plus sinterhip process was cdopted to prepare ultrafine WCCo cemented carbide. The microstructure, grain size, porosity, density, Rockwell A hardness （ HRA ）, transverse rupture strength （ TRS ） , saturated magnetization and coercivity force were studied. The experimental results show that average grain size of the sample prepared by vacuum sintering plas sinterhip technology was about 420 nm, transverse rupture strength was more than 3460 MPa, and Rockwell A hardness of sintered specimen was more than 92.5. Ultrafine WC- 10Co cemented carbide with high strength and high hardness is obtained.     

Research on Ultrafine WC-10Co Cemented Carbide with High Propertie

1 IntroductionMaterials scientists overthe world have been workingto seek for materials with both high hardness and hightoughness. The ultrafine grained WC-Co (cobalt-bondedtungsten carbide) is one of ideal materialstill now.Nano-crystalline WC-Co cemented carbides have both highhardness and hightoughness[1-8].Submicron hardmetals are used as wear parts ,circu-lar shearing and cutting blades , magnetic video tapes ,chipless formingtools ,dental tools and others .The per-formances of these t…     

超细WC-TiC-Co硬质合金粉体制备及其成型特性

运用ND2型行星式高能球磨机,制备超细WC-TiC-Co硬质合金粉体.研究了WC-5TiC-10Co(YT5)复合粉体的球磨时间和平均粒度的关系及粉体的成型特点.实验结果表明:在转速为200r/min,正反转间歇时间为5min的条件下,球磨12h、60h、144h,可以得到平均粒度分别为0.94μm亚微米级、510nm准纳米级粉体、小于50nm的纳米级粉体;球磨时间达到60h,开始明显出现粉体团聚现象,随着球磨时间的延长,粉体的平均粒度越小,粉体团聚越严重;粉体的振实密度和压坯的密度由高到低的次序都足微米级>准纳米级>纳米级.     

Research of Ultrafine Cemented Carbides for PCB Microdrills

The nanocrystalline WC-10Co composite powders were produced with the processing method of spray thermal decomposition-continuous reduction & carburization. The ...     

Influences of Carbon Content on the Properties and Microstructure of Ultrafine WC-10Co Cemented Carbide

WC-10Co nanocrystalline composite powders prepared by spray pyrogenation-continuous reduction and carburization technology were consolidated by vacuum sintering plus hot isostatic pressing (HIP). Influences of carbon content on properties and microstructure of ultrafine WC-10Co cemented carbide were investigated. The results show that the relative density of the ultrafine WC-10Co cemented carbides can reach 99.72%, and the transverse rupture strength (TRS) was higher than 3 890 MPa, Rockwell A hardness (HRA) was higher than 92.5, the average grain size was less than 460 nm, when carbon content in nanocrystalline composite powder was 5.54wt% and the ball-milled time was 48 hours, ultrafine WC-10Co cemented carbide with excellent properties and homogeneous microstructure was obtained. Funded by the National Natural Science Foundation of China (No.50502026), the Youth Science Plan for Light of the Morning Sun of Wuhan City(No.200750731270), and Key Project for the Science & Technology Research Department, Chinese Ministry of Education (No.105123)     

Influences of Carbon Content on the Properties and Mierostrueture of Ultrafine WC-10Co Cemented Carbide

WC-10Co nanocrystalline composite powders prepared by spray pyrogenation-continuous reduction and carburization technology were consolidated by vacuum sintering plus hot isostatic pressing （HIP）. Influences of carbon content on properties and microstructure of ultrafine WC-10Co cemented carbide were investigated. The results show that the relative density of the ultrafine WC-10Co cemented carbides can reach 99.72%, and the transverse rupture strength （TRS） was higher than 3 890 MPa, Rockwell A hardness （HRA） was higher than 92.5, the average grain size was less than 460 nm, when carbon content in nanocrystalline composite powder was 5.54wt% and the ball-milled time was 48 hours, ultrafine WC-10Co cemented carbide with excellent properties and homogeneous microstructure was obtained.     

硬质合金高温化学气相沉积TiC涂层工艺研究

采用高温化学气相沉积在YG8基体上制备TiC涂层, 研究沉积温度、沉积时间、H₂流量、H₂/CH₄(流量比)以及TiCl₄流量对镀层的抗弯曲强度、膜基结合力及表面显微硬度的影响, 并通过正交试验优化工艺参数。结果表明:当沉积温度为1 000℃, 沉积时间为90 min, H₂流量为400 ml, H₂/CH₄(流量比)为15:1, TiCl₄流量为80 mL时, 镀层具有优良的性能, 抗弯曲强度达到1 100 N, 表面显微硬度达到3 228 HV, 膜基结合力达到90 N。       

硬质合金刀片切削性能的实验研究

对硬质合金刀片的切削性能进行了实验研究,分别对常规磨削和经精磨后的数控刀片在切削加工中的磨损情况进行了对比。实验证明,在同样切削参数条件下,利用精磨后的数控刀片进行切削加工,不仅提高了加工精度,而且降低了刀片的磨损速度,延长了刀片的使用寿命,从而节省了刀片的购置费用。     

Influence of Thermal Load on Mechanical Property of Cemented Carbide Material and Heavy Cemented Carbide Inserts Life

A large amount of cutting heat is produced during the heavy cutting process,and insert life is restricted by the effect of thermal load.The thermal load experiment of cemented carbide SCS,WF and YT15 is carried out,and the results show that the bending strength and fracture toughness of cemented carbide material decrease obviously under cyclic thermal load,while in the cooling process,the material mechanical property changes worse suddenly.The high-temperature mechanical property of SCS is the most stable,and that of YT15 is the worst.Further,a relation model among cutting temperature,cutting parameters and insert life is established.Finally,the measures to improve heavy cemented carbide inserts life are summarized from the aspects of cutting parameters selection,insert optimization design and TiCN,Al2O3,TiN complex insert coating.The research results are expected to provide support and reference for heavy cutting technology and insert technology.