调制比对TiN/Ti多层膜结构和力学性能的影响

采用反应磁控溅射的方法在Ti6Al4V基板上沉积(TiN/Ti)n多层膜,交替沉积Ti层和TiN层,以通入/关闭氮气实现对TiN含量的控制.共溅射10层,每层TiN膜和Ti膜的厚度之和即调制周期不变,二者之间的厚度比即调制比分别为1∶9、1∶5、1∶3和1∶2.利用XRD、SEM分别研究了薄膜的微观结构和表面形貌,利用显微硬度仪和划痕仪测量了薄膜的硬度和膜基结合力.研究结果表明:随着调制比的增大,TiN(200)逐渐消失,出现Ti2N等新相;硬度、结合力有明显增大的趋势,与单层膜相比,多层膜的硬度和结合力最多分别增加250 HV和22 N.     

ARZ陶瓷颗粒增强316L不锈钢复合材料的制备及性能

采用粉末冶金工艺制备了Al₂O₃增强ZrO₂(alumina reinforced zirconia,ARZ)陶瓷颗粒增强316L不锈钢(316L不锈钢/ARZ)复合材料，研究了ARZ陶瓷颗粒体积分数对316L不锈钢/ARZ复合材料的微观组织、相对密度、硬度、耐磨性的影响。结果表明：当ARZ陶瓷颗粒体积分数为20%时，复合材料的相对密度达到97.53%，与不锈钢基体相当；继续加入ARZ陶瓷，陶瓷颗粒发生团聚降低了复合材料相对密度。316L不锈钢/ARZ复合材料的硬度随着ARZ陶瓷颗粒体积分数的增高而增大，当ARZ陶瓷颗粒的体积分数为60%时，复合材料的硬度达到最大值HRB 96.8。复合材料耐磨性优于不锈钢基体，其中含有体积分数为60%ARZ陶瓷颗粒的复合材料体积磨损率较基体减少了4.2倍；随着ARZ陶瓷颗粒含量的增加，复合材料的耐磨性提高，复合材料的磨损机理主要为316L不锈钢的剥落。     

V含量对(Ti,V)C35CrMo钢结硬质合金组织与力学性能的影响

用原位烧结法制备了不同V与Ti原子比(0,0.2,0.4,0.8)的(Ti,V)C35CrMo钢结硬质合金.研究了V含量对钢结硬质合金组织及力学性能的影响.用SEM 观察试样的微观组织特征、断口形貌和磨损形貌.结果表明:V含量影响钢结硬质合金硬质相的形态、大小、体积分数,进而影响合金的力学性能.V与Ti的原子比为0.2时硬质相最小;随着V含量增加,硬质相趋于圆整、并增大.断口形貌特征为硬质相解理、基体准解理及韧窝.基体形变磨损和硬质相脱落是钢结硬质合金的磨料磨损机理.V与Ti的原子比为0.2时抗弯强度及耐磨性最高.     

不同偏压下Cr/CrCN涂层在3.5%NaCl环境下的电化学及摩擦学行为

研究通过电弧离子镀方法在304L不锈钢及Si片上沉积Cr/CrCN涂层,通过改变基体偏压(30 V,60 V,90 V,120 V)来探讨涂层在3.5%(质量分数,下同)NaCl溶液中的电化学与摩擦学行为。研究结果表明:随着基体偏压的增加,涂层的硬度呈现递增的趋势,在基体偏压为120 V时达到最高,约为29 GPa;而临界载荷、韧性及耐蚀性则呈现先递增后递减的趋势,在基体偏压为90 V时达到最佳;当基体偏压由30 V上升到90 V时,涂层在3.5%NaCl溶液中的摩擦系数和磨损率分别由0.34和1.78×10~(-6)mm~3/Nm下降为0.21和7.8×10~(-7)mm~3/Nm,当基体偏压进一步上升时,涂层的摩擦磨损性能则开始下降。基体偏压对Cr/CrCN涂层在3.5%NaCl中的电化学与摩擦学行为有着重要影响,基体偏压为90 V时涂层的防腐耐磨性能最为优异。     

烧结温度对Ti(C,N)-HfN/Ti(C,N)-WC层状陶瓷微观组织和力学性能的影响

以Ti(C,N)为基体相,HfN和WC为不同层的增强相,金属Ni和Mo为粘结相,采用交替铺层法制备素坯,并利用真空热压烧结技术制备Ti(C,N)-HfN/Ti(C,N)-WC层状陶瓷,研究了烧结温度对层状陶瓷微观组织和力学性能的影响。结果表明：随着烧结温度的升高,材料中的晶粒逐渐长大,在烧结温度为1350℃和1400℃时,材料的晶粒较小但分布不均匀,且存在较多的微缺陷;在烧结温度为1450℃和1500℃时,材料中的晶粒相对均匀（粒径～1μm）,微缺陷较少;在烧结温度达到1550℃时,材料中出现了大量粗大晶粒（粒径～2μm）。随着烧结温度的升高,层状陶瓷的抗弯强度、维氏硬度和断裂韧度均先增大后减小。在1450℃下所制备的Ti(C,N)-HfN/Ti(C,N)-WC层状陶瓷具有较好的综合力学性能,其抗弯强度、维氏硬度和断裂韧度分别为(1263.6±17.1)MPa、(18.5±0.3)GPa和(8.2±0.1)MPa·m1/2。此外,Ti(C,N)-HfN/Ti(C,N)-WC层状陶瓷在断裂时表现为穿晶与沿晶并存的断裂模式。     

沉积工艺对磁控溅射TiAlN薄膜微观形貌及性能的影响

采用非平衡磁控溅射技术在Q235钢基体上制备了TiAlN薄膜,研究了沉积工艺参数对薄膜微观形貌、力学性能及耐腐蚀性能的影响规律,通过扫描电镜、纳米力学探针、划痕测试仪对薄膜的微观形貌和力学性能进行表征,并利用盐雾试验和电化学极化测试研究了薄膜在含Cl-环境中的腐蚀行为。结果表明,随着N_2流量的升高,TiAlN薄膜的硬度和结合力先升高后降低,当N_2流量为10sccm时,薄膜具有最高的硬度和结合力,分别为30.7GPa和44.2N,其耐腐蚀性能最优。随着Al靶功率的增加,薄膜的硬度和结合力先增大后减小,当Al靶功率为90W时,薄膜的硬度和结合力达到了最大值,分别为28.6GPa和38.4N,具有最佳的抗腐蚀性能。随着基体温度的升高,薄膜的硬度和结合力逐渐增大,基体温度低于300℃时,增大幅度较明显,基体温度高于300℃时,二者增加幅度趋于平缓,薄膜表现出优异的耐腐蚀性能。     

碳纤维添加量对Ti(C,N)基金属陶瓷材料组织和性能的影响

以Ti(C,N)、Mo_2C、Co、Ni、WC和C_f(碳纤维)为原料,通过粉末冶金工艺制备了不同添加量C_f增强Ti(C,N)基金属陶瓷材料,研究了C_f添加量对金属陶瓷密度、硬度和抗弯强度的影响。结果表明,随着C_f添加量的逐渐增大,Ti(C,N)基金属陶瓷材料密度和硬度略有降低,抗弯强度先增大后减小;当C_f添加量(质量分数)为2%时,Ti(C,N)基金属陶瓷材料力学性能最佳,此时硬度为66 GPa,抗弯强度为672.6 MPa。     

原始成分组成对Ti(C,N)基金属陶瓷烧结性能的影响

采用真空烧结工艺制备了Ti(C,N)基金属陶瓷,研究了原始成分组成对材料烧结特性和力学性能的影响规律。结果表明:保持Mo/(Mo+Ni)为定值,随着硬质相成分的增加,烧结体抗弯强度降低,硬度增加;硬质相成分TiN含量超过一定阈值时,烧结体疏松导致硬度和抗弯强度同时大幅下降;TiN含量保持定值,硬质相成分含量增加,烧结体硬度增加,抗弯强度下降;粘结相成分用Co部分替代Ni,随Co含量的增加,烧结体硬度略有升高的基础上抗弯强度升高。     

316L不锈钢表面沉积CrCN薄膜的结构及性能研究

利用多弧离子镀技术在316L不锈钢和单晶硅上沉积CrCN薄膜,通过X射线衍射仪(XRD)、扫描电镜(SEM)、X射线光电子能谱仪(XPS)、纳米压痕仪、273A电化学工作站和多功能摩擦磨损试验机等对316L不锈钢及CrCN薄膜的微观结构、力学性能、耐腐蚀性能和摩擦学性能进行表征.结果表明:在316L不锈钢上沉积CrCN薄膜后,硬度从4 GPa提高到22 GPa,H/E和H3/E2分别从0.022和0.002 GPa提高到0.071和0.11 GPa;阳极腐蚀电位从-0.21 V上升到-0.19 V;在大气,去离子水,海水环境下的摩擦系数及磨损率均显著降低,表现出较优异的综合性能.     

Ti,C质量比对固溶态1515Ti奥氏体不锈钢显微组织的影响

采用光学显微镜(OM),扫描电子显微镜(SEM)等设备研究了不同Ti,C质量比的1515Ti奥氏体不锈钢在1200℃下保温不同时间后的组织演变.结果表明,当Ti,C质量比为4时,合金析出颗粒状的TiC,当Ti,C质量比为6和8时,富余的Ti原子与基体中的C与N原子反应,导致合金还析出了枝晶状Ti(C,N),且Ti,C质量比由6升高至8后,枝晶状Ti(C,N)的数量也随之增多.随着保温时间的延长,不同Ti,C质量比合金析出颗粒状TiC与枝晶状Ti(C,N)的数量逐渐增多.然而,当合金在1180℃保温2h的条件下进行固溶处理时, Ti,C质量比对显微组织无明显影响,合金均析出少量颗粒状的TiC.     

（W，Ti，Ta）C复式碳化物对WC-（6％-8％）Co超细硬质合金性能的影响

以WC-6％Co和WC-8％120为研究体系,在1390℃压力烧结下制备不同配比复式碳化物的超细硬质合金。分别采用洛氏硬度检测、抗弯强度检测、钴磁检测、矫顽磁力检测等方法,通过扫描电镜和电子衍射分析,研究了不同量的（W,Ti,Ta）C复式碳化物对超细硬质合金性能的影响。结果表明：WC-6％Co-2％（W,Ti,Ta）C超细硬质合金的矫顽磁力为45．39kA·m^-1,硬度为94．0HRA,抗弯强度为2280MPa;WC-8％Co-2％（w,Ti,Ta）C超细硬质合金的矫顽磁力为37．4kA·m^-1,硬度为93．4HRA,抗弯强度为2670MPa;WC-8％Co-2％（w,Ti,Ta）C-0．5％（Cr3C2/VC）的矫顽磁力为38．2kA·m^-1,硬度为93．6HRA,抗弯强度为2780MPa;它们具有较高的综合性能。     

High temperature oxidation resistance of CrN/(Ti,Al,Zr,Cr)N bilayer films deposited by multi-arc ion plating

CrN/(Ti,Al,Zr,Cr) N bilayer films were successfully deposited on cemented carbide( WC-8% Co) substrates by multi-arc ion plating process using two Ti-Al-Zr alloy targets and one pure Cr target. As a result of bilayered structure and addition of alloying elements( e. g. Al and Cr),the films exhibited excellent high temperature oxidation resistance under both short-term isothermal( up to 800 ℃) and long-term cyclic( up to 600 ℃) exposure conditions. Combined with pre-established outstanding tribological properties( e. g. maximum hardness of 4 000HV0. 01 and maximum adhesion strength over 200 N),these observations make such films quite a promising candidate to extend the cutting tool life span and boost the performance in high-productivity,high-speed and high-feed cutting or in dry machining conditions.     

Active wear and failure mechanisms of TiN-Coated high speed steel and tin-coated cemented carbide tools when machining powder metallurgically made stainless steels

In this study, active wear and failure mechanisms of both TiN-coated high speed steel and TiN-coated cemented carbide tools when machining stainless steels made by powder metallurgy in low and high cutting speed ranges, respectively, have been investigated. Abrasive wear mechanisms, fatigue-induced failure, and adhesive and diffusion wear mechanisms mainly affected the tool life of TiN-coated high speed steel tools at cutting speeds below 35 m/min, between 35 and 45 m/min, and over 45 m/min, respectively. Additionally, fatigue-induced failure was active at cutting speeds over 45 m/min in the low cutting speed range when machining powder metallurgically made duplex stainless steel 2205 and austenitic stainless steel 316L. In the high cutting speed range, from 100 to 250 m/min, fatigue-induced failure together with diffusion wear mechanism, affected the tool life of TiN-coated cemented carbide tools when machining both 316L and 2205 stainless steels. It was noticed that the tool life of TiN-coated high speed steel tools used in the low cutting speed range when machining 2205 steel was longer than that when machining 316L steel, whereas the tool life of TiN-coated cemented carbide tools used in the high cutting speed range when machining 316L steel was longer than that when machining 2205 steel. formerly with the Laboratory of Engineering Materials, Helsinki University of Technology     

Co和Cr3C2对硬质合金组织和性能的影响

采用粉末冶金工艺制备了三种不同Co和Cr3C2含量的硬质合金材料。在常温下分别测量了材料的晶粒度、硬度和抗弯强度,并通过SEM照片等对材料的金相显微组织、断口形貌进行分析。结果表明:硬质合金中粘结相Co含量增多,其硬度下降,抗弯强度升高;微量碳化物Cr3C2在硬质合金中起到细化晶粒的作用,在高钴硬质合金中添加微量碳化物Cr3C2,能使材料具有高硬度、高抗弯强度的良好综合性能。     

Adherent Ti(C,N) Coatings on Cemented Carbide Substrates with Fe/Ni/Co Binder

Both hard CVD coatings deposited on cemented carbides and the use of innovative binders for Co-bonded cemented carbide attract worldwide interest. In this article, ISO grade P30 cemented carbides are prepared with Fe Ni and Co binder, and adherent Ti(C,N) coatings are deposited on all the substrates by moderate-temperature chemical vapor deposition (MTCVD). The microstructure and properties of the cemented carbides before and after coating process are studied. The results show that Ti(C,N) coatings on all the substrate show compact and well-developed columnar structures, and high adhesion strength can be achieved.     

Investigation of Microwave Processing Parameters on Development of Ni-40Cr3C2 Composite Clad and Their Characterization

Metallurgical and Materials Transactions A - The chromium carbide (Cr3C2)-reinforced Ni-based composite clad on austenitic stainless steel (SS-316) substrate was successfully developed by the...     

The effect of V/Ti ratio on the partitioning of mo in (V,Ti) + (Ni,Mo) cemented carbides

The performance of a series of (V,Ti)C + (Ni,Mo) cermet systems with a given Mo content and varying V/Ti ratios in the carbide has been evaluated through hardnessvs crack resistance plots. It is shown that the partitioning of Mo between the binder and the carbide in these cermets is sensitive to the V/Ti ratio of the carbide. For both low and high V/Ti ratios, most of the Mo is in the carbide phase, but through different mechanisms. For intermediate V/Ti ratios, most of the Mo is in solid solution in the binder and provides strengthening. The best overall system performance is achieved when this ratio is close to unity, as borne out by the crack resistancevs hardness comparisons.     

Carbide-binder interface ledges in (V,Ti) C+ (Ni,Mo) cermets

Interface ledges have been observed by transmission electron microscopy between the carbide and binder phases in (V, Ti) C+ (Ni, Mo) cemented carbides. It is proposed that these ledges can act as dislocation sources in a manner analogous to that of polycrys-talline metals and alloys. Such a concept can provide a physical basis for the empirically observed relation between hardness and the binder mean free path in cemented carbides. R. K. VISWANADHAM, formerly with Martin Marietta Laboratories, 1450 S. Rolling Road, Baltimore, MD 21227     

铌与钛对铁素体不锈钢析出和成形性的影响

研究了铌、钛对铁素体不锈钢析出相、织构和成形性的影响。结果显示:添加铌、钛后的析出相主要是TiN和(Nb,Ti)C,其析出尺寸分别为4μm和200 nm;同时,铌、钛的添加抑制了冷轧薄板α纤维织构的生长,促进了γ纤维织构强度的增加。添加稳定化元素铌、钛后,冷轧薄板的平均r值由1.05增加到1.46,起皱高度也由29.1μm下降到18.9μm,薄板成形性能的改善同再结晶织构的变化密切相关。     

TiC?NiCrCoMo钢结硬质合金的制备与高温氧化性能

以镍基合金（NiCrCoMo）为粘结相,以碳化钛（TiC）为硬质相,通过粉末冶金技术制备出抗高温氧化的TiC?NiCrCoMo钢结硬质合金。通过优化烧结工艺得到综合性能最佳的TiC?NiCrCoMo钢结硬质合金,测定了钢结硬质合金在不同温度下的氧化动力学曲线,并分析了氧化层的显微形貌。结果表明,经1280 ℃烧结的TiC?NiCrCoMo钢结硬质合金综合性能最佳,密度为6.01 g/cm3,硬度为HRC 65,抗弯强度为1100 MPa。随着氧化温度的升高,TiC?NiCrCoMo钢结硬质合金的氧化程度明显增加;通过与316L不锈钢钢结硬质合金的氧化动力学曲线对比发现,TiC?NiCrCoMo钢结硬质合金具有优异的抗高温氧化性能。