NiTi合金表面改性及其微动磨损性能研究

采用多弧离子镀技术在NiTi形状记忆合金表面制备TiN涂层。利用SRVⅢ摩擦磨损试验机研究NiTi合金表面改性后在37℃Hank’s模拟体液中微动磨损性能,分析法向载荷对TiN合金磨损机制的影响规律。利用SEM扫描电镜及能谱考察磨损表面形貌,结果表明：制备的TiN涂层表面致密均匀,无明显缺陷。说明TiN涂层可有效提高基体的耐磨性能,其磨损机制主要表现为剥落损伤与磨粒磨损并存。TiN涂层显微硬度为784 HV,远高于基体,TiN/NiTi膜基硬度比缓慢下降,涂层与基体结合强度高。     

ZrN涂层刀具的滑动磨损特性研究

山东大学摘要:采用电弧离子镀法在硬质合金刀具表面制备了厚度为2.19~5.23μm的ZrN系列涂层,测定了涂层的显微硬度,并通过划痕试验和摩擦磨损试验考察了涂层与基体的结合强度及其摩擦磨损性能。在扫描电镜下观察磨损表面形貌,结果表明:ZrN系列涂层能够显著提高硬质合金刀具的表面硬度;涂层与基体的结合强度较高,划痕临界载荷高于60N;与此同时,电弧离子镀法ZrN系列涂层可以显著改善硬质合金刀具的耐磨性能。磨损机理主要是磨粒磨损和涂层的微剥落。     

MoS2／Zr复合涂层高速钢刀具的切削性能研究

采用中频磁控溅射和多弧离子镀相结合的工艺在M2高速钢麻花钻表面沉积制备了MoS2/Zr复合涂层,考察了复合涂层的表面形貌及力学性能,在干式切削条件下研究了复合涂层刀具钻削45钢的切削性能.结果表明,与纯MoS2 涂层相比,MoS2/Zr 复合涂层的硬度显著提高,与无涂层高速钢刀具相比,MoS2/Zr复合涂层刀具的切削能力提高了约4倍.复合涂层的存在使得刀具主切削刃的后刀面磨损量明显减小,刀具的黏结磨损和磨粒磨损程度显著降低.MoS2/Zr复合涂层刀具后刀面和横刃的磨损形式主要为涂层的分层剥落,同时伴随有一定程度的黏结磨损和磨粒磨损.     

解析刀具磨损与刀具寿命

1．涂层技术有效改善刀片切削区域性能 金属切削过程中所产生的功率消耗以切削热和摩擦的形式表现出来。这些因素使刀具处于恶劣的加工条件下,表面高负载、高切削温度。之所以产生高温是因为切屑沿刀具前刀面高速滑移,对切削刃产生高压及强烈的摩擦。     

硬质合金刀具高能离子源增强多弧镀AlCrTiSiN梯度涂层制备及性能研究

采用离子源增强的多弧离子镀新技术,在硬质合金刀具表面制备了不同含Si层梯度结构的AlCrTiSiN梯度涂层,并对涂层组织结构、残余应力、结合强度、摩擦磨损以及铣削和钻削加工灰铸铁性能进行了详细的研究。结果表明：不同含Si层梯度结构的AlCrTiSiN涂层主要由固溶的(Al,Cr) N、(Al,Ti) N相和非晶态Si₃N₄相组成。其中,含Si层梯度变化最缓和的G3(Gradient 3)涂层具有较高的结合强度,较低的残余压应力、摩擦因数和磨损率。铣削和钻削试验显示,涂层刀具的切削磨损机理主要表现为磨粒磨损和粘着磨损。G3涂层降低了磨粒磨损,其刀具的铣削和钻削寿命均最高,这主要得益于其含Si层的梯度设计、适当的压应力(-3.8 GPa)以及良好的膜基结合强度。研究结果表明,通过对含Si层进行梯度设计可显著提高涂层刀具的切削性能。     

TiN涂层精密复杂刀具切削特性的研究

本文研究了精密复杂高速钢刀具经TiN涂层后的切削特性、重磨后的特性和高速切削特性。实验证明,经TiN涂层处理的齿轮滚刀可提高切削寿命6倍以上,插齿刀可提高5倍以上,拉刀可拉削HRC25～36的难加工材料,光洁度可提高1级,TiN涂层后的滚刀、插齿刀经重磨开刃后,其切削寿命仍然比未涂层的新刀提高6倍以上,对于齿轮刀具、拉削刀具等刃磨前刃面的刀具,TiN涂层仍然保持刀具的高寿命。     

Ti（C,N）涂层刀具切削磨损数值模拟分析

模拟了在相同切削条件下Ti（C,N）涂层刀具和未涂层刀具切削温度变化情况.验证了Ti（C,N）涂层材料能降低切削力、减小切削热,保护切削刃,避免产生崩刃的作用;验证了刀具前刀面靠近主切削刃处容易磨损是由于在高速切削加工中,切削温度高,导致粘结、氧化和扩散磨损加剧造成的.     

涂层刀具切削铁基粉末冶金复合材料时的磨损机理

研究了切削NbC颗粒增强铁基粉末冶金复合材料时的刀具磨损性能及其机理.研究表明,涂层刀具的耐磨性稍优于超细晶粒及普通硬质合金刀具,涂层刀具前刀面主要发生磨粒磨损,由此引起涂层的剥落和前刀面月牙洼的形成,最终导致刀尖部位产生崩刃,而后刀面磨损主要由磨粒磨损引起.此外,加工过程中刀具还会产生轻微粘结磨损.     

TiCN涂层硬质合金刀具铣削性能研究

采用Kistler三向压电铣削测力仪测试了刀具切削45钢过程中的切削力,利用超景深显微镜、扫描电镜和能谱仪观察分析刀具切削后的磨痕宽度、形貌和成分,获得了未涂层刀具HSS、TiN和TiCN涂层刀具的切削时间与磨痕宽度关系图,探讨了刀具的切削失效机理。采用XRD分析了涂层刀具铣削前的相结构,结果表明:TiN与TiCN涂层均表现为fcc-TiN相结构,TiCN具有明显的(111)择优取向,TiN择优取向不明显。切削试验表明:在磨痕宽度达到0.3mm时,TiCN涂层刀具的切削时间比TiN涂层刀具切削时间约长2.5倍,同时整个切削过程中TiCN比TiN具有更低的切削力。这可能是因为TiCN涂层比TiN涂层具有更高的硬度和耐磨性,并且切削过程中TiCN涂层中固溶的C能析出至晶界处,起到润滑作用,降低刀具与工件材料之间的摩擦,减小切削力,延长刀具使用寿命。SEM和EDS分析表明:TiN涂层刀具磨损失效机理为磨料磨损和粘着磨损,而TiCN涂层刀具失效以磨料磨损为主。     

/Zr复合涂层高速钢刀具的切削性能研究

采用中频磁控溅射和多弧离子镀相结合的工艺在M2高速钢麻花钻表面沉积制备了MoS₂/Zr复合涂层,考察了复合涂层的表面形貌及力学性能,在干式切削条件下研究了复合涂层刀具钻削45钢的切削性能。结果表明,与纯MoS₂ 涂层相比,MoS₂/Zr 复合涂层的硬度显著提高,与无涂层高速钢刀具相比,MoS₂/Zr复合涂层刀具的切削能力提高了约4倍。复合涂层的存在使得刀具主切削刃的后刀面磨损量明显减小,刀具的黏结磨损和磨粒磨损程度显著降低。MoS₂/Zr复合涂层刀具后刀面和横刃的磨损形式主要为涂层的分层剥落,同时伴随有一定程度的黏结磨损和磨粒磨损。     

ZrN/TiN复合涂层刀具的制备及其磨损性能研究

采用中频磁控溅射和电弧离子镀两种方法组合在硬质合金基体上沉积ZrN／TiN复合涂层，采用切削试验来研究ZrN／TiN涂层对硬质合金刀具切削性能的影响。结果表明：ZrN／TiN复合涂层提高了硬质合金刀具的硬度，涂层刀具的显微硬度受基体硬度的影响，基体YG6、YT14涂层后的显微硬度分别可达2300HV，2500HV；使涂层刀具切削力的降低了20％；提高了涂层刀具的耐磨损能力。     

不同涂层刀具切削淬硬H13钢加工性能研究

为了研究不同涂层刀具切削淬硬H13钢的切削性能,进行了多层Ti化合物涂层、TiAlN涂层以及MTTiCN厚Al_2O_3TiN涂层材料刀具车削加工淬硬H13钢试验,分析了不同的涂层材料刀具与切削力、切削温度、涂层刀具磨损以及刀具寿命的关系。研究得出:多层Ti化合物涂层刀具受到三个方向的力都大于其它两种涂层的刀具,而且切削温度最高;用TiAlN涂层刀具切削时温度最低;切削过程中三种刀具后刀面磨损程度不同,发现多层Ti化合物涂层刀具磨损最为严重,寿命最短;MT-TiCN厚Al_2O_3Ti N涂层材料刀具比多层Ti化合物涂层刀具寿命长30%;TiAlN涂层刀具的切削寿命最长比多层Ti化合物涂层刀具寿命长45%。     

High-Speed Machining of Malleable Cast Iron by Various Cutting Tools Coated by Physical Vapor Deposition

The coating material of a tool directly affects the efficiency and cost of machining malleable cast iron.However,the machining adaptability of various coating materials to malleable cast iron has been insufficiently researched.In this paper,turning tests were conducted on cemented carbide tools with different coatings(a thick TiN/TiAlN coating,a thin TiN/TiAlN coating,and a nanocomposite(nc)TiAlSiN coating).All coatings were applied by physical vapor deposi-tion.In a comparative study of chip morphology,cutting force,cutting temperature,specific cutting energy,tool wear,and surface roughness,this study analyzed the cutting characteristics of the tools coated with various materials,and established the relationship between the cutting parameters and machining objectives.The results showed that in malleable cast iron machining,the coating material significantly affects the cutting performance of the tool.Among the three tools,the nc-TiAlSiN-coated carbide tool achieved the minimum cutting force,the lowest cutting tempera-ture,least tool wear,longest tool life,and best surface quality.Moreover,in comparisons between cemented-carbide and compacted-graphite cast iron machined under the same conditions,the wear mechanism of the coated tools was found to depend on the cast iron being machined.Therefore,the performance requirements of a tool depend on multiple factors,and selecting an appropriately coated tool for a particular cast iron material is essential.     

PCVD直流脉冲沉积温度对TiN／TiSiN复合涂层高温氧化性能的影响

采用工业用直流脉冲等离子体增强化学气相沉积（PCVD）法在硬质合金刀具材料上制备了TiN／TiSiN复合涂层。对比研究了TiN及不同温度制备的TiN／TiSiN复合涂层高温抗氧化性能。研究表明：含有非晶阻隔抗氧化结构si3N。的TiN／TiSiN复合涂层高温氧化性能远高于TiN涂层,TiN／TiSiN复合涂层提高到800℃,仍可避免出现较大面积氧化及脱落;PCVD直流脉冲沉积制备温度对涂层高温抗氧化能力有重要影响,550℃沉积制备的致密、均匀、颗粒小的复合涂层高温氧化性能最佳,600℃次之,500％最差。     

正交车铣高强度钢的刀具耐用度及磨损机理研究

通过TiN涂层硬质合金端铣刀正交车铣58SiMn高强度钢的刀具磨损试验,建立了刀具耐用度T-(vc,fa,fz)关系泰勒公式,分析了各切削用量对刀具耐用度的影响关系;对正交车铣刀具的磨损研究表明刀具表面材料的疲劳—剥落和切削刃微崩以及在高温下刀具材料中的元素与周围介质发生的化学反应磨损等是造成刀具磨损的主要原因。     

Investigation on the bonding strength patterns of ultrasonic vibration tools and influence on working performance during rotary ultrasonic grinding

During rotary ultrasonic grinding process, working performance of ultrasonic vibration tools varies according to the bonding patterns between diamond grit and bond. In order to understand the influence of ultrasonic vibration tools on working performance, bonding patterns and bonding strength of ceramic-bonded, iron-bonded, and bronze-bonded tools were investigated. Influence of bonding strength on cutting force, tool wear, surface quality, and edge breakout were studied, coupled with the characteristics of ultrasonic vibration tools. The results show that cutting force in Z axis and tool wear reduce with the increase of bonding strength while the surface quality and edge breakout become worse.     

Measuring procedures of cutting edge preparation when hard turning with coated ceramics tool inserts

In this paper, the authors introduce the methodology of combined studies on cutting edge preparation and tool performance testing. Five main fields of research on cutting edge preparation are identified in this study of cutting edge preparation while cutting edge microgeometry consists of data associated with tool edge and rake face. Uncoated and TiN coated mixed oxide ceramics inserts have been tested concerning their microgeometry and wear resistance and there is presented a sequence of measuring to identify cutting edge preparation and properties of coating. Authors propose the sequence which considers cutting edge preparation as a factor controlling performance of cutting edge in hard turning operations. Four steps in the sequence of performance testing include measurements with effects of wear criterion and machining time. Measured results show that combined effects of both preparation and coating reduce considerably friction forces in scratch tests and there is very negligible change of microhardness of uncoated and coated ceramics. Relationships between cutting edge microgeometry and acceptable machined surface roughness which results from the sequence in tool performance testing have been identified. Finally, tool performance indices are based on units which characterize machined surface roughness, tool edge wear and forces when hard turning.     

涂层Si_3N_4陶瓷刀具切削性能研究

研究了不同切削参数对TiN+Al2O3涂层氮化硅陶瓷刀具切削灰铸铁的切削性能的影响,使用工具显微镜、SEM/EDS手段分析了涂层氮化硅刀具的磨损机理,实验还采用相同基体氮化硅陶瓷刀具做了对比分析。研究结果显示TiN+Al2O3涂层氮化硅刀具可以承受比较大的切削用量,对提高加工效率有重大意义;还发现涂层氮化硅陶瓷刀具主要失效形式为磨粒磨损,粘结磨损,在较高切削速度条件下前刀面还会出现因化学磨损形成的月牙洼。     

Wear behavior and cutting performance of nanostructured hard coatings on cemented carbide cutting tools in hard milling

The influence of nanolayer AlTiN/TiN and multilayer nanocomposite TiAlSiN/TiSiN/TiAlN hard coatings on the wear behavior and cutting performance of carbide cutting tools was investigated in face milling of hardened AISI O2 cold work tool steel (∼58 HRC) at dry conditions. Characterization of the coatings was performed using nanoindentation, scratch test, reciprocating multi-pass wear test. The chips forming during cutting process were also analyzed. Results showed that abrasive and oxidation wear are dominant tool failures. The nanolayer AlTiN/TiN coating gives the best adhesion to the substrate, the best wear resistance in machining and thus provides the longest lifetime with carbide inserts.     

Evaluation on Effectiveness of CVD and PVD Coated Tools during Dry Machining of Incoloy 825

With wide applications of nickel-based superalloys in strategic fields, it has become increasingly necessary to evaluate the performance of different advanced cutting tools for machining such alloys. With a view to recommend a suitable cutting tool, the present work investigated various machinability characteristics of Incoloy 825 using an uncoated tool, chemical vapor deposition (CVD) of a bilayer of TiCN/Al₂O₃, and physical vapor deposition (PVD) of alternate layers of TiAlN/TiN-coated tools under varying machining conditions. The influence of cutting speed (51, 84, and 124 m/min) as well as feed (0.08, 0.14, and 0.2 mm/rev) was comparatively evaluated on surface roughness, cutting temperature, cutting force, coefficient of friction, chip thickness, and tool wear using different cutting tools. Although the CVD-coated tool was not useful in decreasing surface roughness and temperature, a significant reduction in cutting force and tool wear could be achieved with the same coated tool under a high cutting speed of 124 m/min. On the other hand, the PVD-coated tool outperformed the other tools in terms of machinability characteristics. This might be attributed to the excellent antifriction and antisticking property of TiN and good toughness due to the multilayer configuration in combination with a thermally resistant TiAlN phase. Adhesion, abrasion, edge chipping, and nose wear were the prominent wear mechanisms of the uncoated tool, followed by the CVD-coated tool. However, remarkable resistance to such wear was evident with the PVD TiAlN/TiN multilayer-coated tool.