两步压入法--薄膜力学性能的可靠测量方法

提出了采用力学探针测量薄膜力学性能的两步压入法.该方法通过大载荷压入展示基体变形对薄膜硬度的影响,从而选择不影响基体变形的小载荷测出薄膜的硬度和弹性模量.对高速钢基片上的TiN硬质薄膜,单晶硅片上的金属Ni薄膜和(Ti,Al)N/VN纳米多层膜的测量表明,两步压入法能够测出各种性质薄膜的力学性能,并且具有准确可靠的特点.此外,两步法对(Ti,Al)N/VN纳米多层膜的力学性能的测量表明,该体系的纳米多层膜存在硬度和弹性模量异常升高的超硬、超模量效应.     

刀具表面超晶格TiN/AlN纳米多层膜的制备和研究

采用脉冲多弧离子镀技术制备TiN/AlN纳米多层膜,随着调制周期的减小,稳定态六方AlN相逐渐转变成亚稳态立方AlN相,形成以TiN/AlN超晶格结构为主的超硬薄膜。与标准图谱的对比可知,TiN/AlN超晶格是AlN在模板立方TiN材料的影响下,在TiN层上以亚稳态相立方结构外延生长所形成。试验表明TiN/AlN薄膜具有良好的耐腐蚀性能以及使用寿命。     

调制周期对纳米多层类石墨薄膜力学性能及摩擦学性能的影响

采用等离子增强多靶磁控溅射系统在溅射沉积类石墨(Graphite-like carbon,GLC)薄膜过程中交替掺杂金属W制备了6种纯GLC子层和W-GLC子层交替堆垛的纳米多层GLC薄膜。薄膜调制周期分别为300 nm、180 nm、90 nm、40 nm、15 nm以及8 nm共6种。研究了调制周期对薄膜力学性能和摩擦学性能的影响。结果表明:各纳米多层GLC薄膜均具有良好的力学性能与摩擦学性能,且随着调制周期的减小,薄膜的力学性能与摩擦学性能均大幅提高,并表现出显著的协同效应。纳米多层GLC薄膜中WC或W_2C纳米晶的弥散强化效应和纳米多层膜的界面效应是薄膜具有优异力学性能的主要原因,而薄膜在摩擦对偶表面形成的厚实致密的富碳转移膜又确保了薄膜具有良好的摩擦学性能。当调制周期减小至8 nm时,薄膜的硬度高达35.13 GPa,结合强度为45.28 N,H/E为0.109 5,H~3/E~2为0.375,且在"100 r/min,12 N"条件下连续摩擦480 min,平均摩擦因数仅为0.002,磨损率低至9.0×10~(-18)m~3/(N·m),综合性能极为优异。     

TiAlN/AlON纳米多层涂层的微观结构和力学性能研究

通过磁控溅射制取一系列不同AlON厚度的TiAlN/AlON纳米多层涂层,并用X射线衍射、扫描电镜、高分辨透射电镜和纳米压痕仪分别对微观结构和力学性能进行表征和测量。研究表明:非晶态的AlON在厚度约小于1 nm时,在TiAlN模板作用下转变为晶体结构,并与TiAlN呈共格外延生长,出现超硬效应,当AlON厚度为0.7 nm时,硬度和弹性模量分别最高可达38.1 GPa和385.6 GPa。当AlON厚度超过1 nm时,逐渐转变为非晶结构并且破坏了多层涂层的共格外延生长,硬度随之降低。因此利用这种机制可以制备出力学性能好、耐高温氧化性的刀具涂层,满足现代切削的需要。     

Al/TiN软硬交替多层膜的制备及摩擦磨损性能研究

软硬交替的多层膜体系具有超硬、强韧、耐磨、自润滑的优势,能大大提高金属切削刀具在现代加工过程中的耐用度和适应性。设计Al/TiN软硬交替纳米多层膜体系,并采用直流磁控溅射和阴极弧磁过滤等离子体沉积相结合的技术,室温下在单晶硅Si（100）衬底上制备一系列不同TiN层厚度纳米多层膜,研究其结构、形貌、力学及摩擦磨损性能。结果表明：该涂层具有良好的多层结构,多层膜中Al呈非晶态或纳米晶态,TiN结晶质量随其厚度增加得到提高;Al/TiN多层膜硬度均高于混合法则计算的硬度值,出现了硬度增强效应;该多层膜体系虽具有较高的摩擦因数,但表现出较好的韧性。     

刀具表面超晶格TiN／AIN纳米多层膜的制备和研究

采用脉冲多弧离子镀技术制备TiN／AIN纳米多层膜，随着调制周期的减小，稳定态六方AIN相逐渐转变成亚稳态立方AIN相，形成以TiN／AIN超晶格结构为主的超硬薄膜。与标准图谱的对比可知，TiN／AIN超晶格是AIN在模板立方TiN材料的影响下，在TiN层上以亚稳态相立方结构外延生长所形成。试验表明TiN／AIN薄膜具有良好的耐腐蚀性能以及使用寿命。     

TiAlN／SiO2纳米多层刀具涂层的微观结构和超硬效应研究

通过磁控溅射方法制取了一系列不同SiO2厚度的TiAlN／SiO2纳米多层涂层,并用X射线衍射仪（XRD）、扫描电镜（SEM）、高分辨透射电镜（HRTEM）和纳米压痕仪分别对该涂层的微观结构和力学性能进行了表征和测量。研究表明：当非晶态的SiO2厚度约小于1nm时,SiO2在TiAlN模板作用下转变为晶体结构,并与TiAlN呈共格外延生长,出现超硬效应;当SiO2厚度为0．6nm时,其硬度和弹性模量分别高达37GPa和393GPa;当SiO2厚度超过lnm时,SiO2逐渐转变为非晶结构并且破坏了多层涂层的共格外延生长,硬度随之降低。因此,可以利用该方法制备出机械性能好且耐高温氧化性的刀具涂层,以满足现代切削的需要。     

超硬纳米多层膜的材料选择与结构设计

综述了近年来超硬纳米多层膜材料选择与结构设计的研究进展,主要介绍了多层膜的选材,从构成多层膜的材料种类、膜与基体的选择、多层膜材料的选择以及从超硬效应理论得到的启示等几个方面总结了多层膜实现超硬特性时要考虑的因素,并指出了目前存在的问题及今后的发展方向。     

磁控溅射沉积TiB_2/DLC纳米多层膜的结构及其机械性能研究

采用非平衡磁控溅射系统在P(100)硅片和304不锈钢基底上制备TiB_2/DLC纳米多层膜。利用FESEM、TEM、XRD和AFM观察多层膜的微观结构和表面形貌;利用纳米压痕仪、维氏硬度计和CSM球-盘摩擦磨损试验机考察TiB_2靶电流对多层膜的机械性能和摩擦学性能的影响。结果表明:TiB_2/DLC多层膜具有良好的多层调制结构,多层膜沿TiB_2(101)晶向择优生长;多层膜的表面粗糙度随着TiB_2靶电流增加而增加;多层膜中的大量异质界面能显著提高薄膜的硬度及韧性,而且当TiB_2靶电流为2.0 A时,多层膜的硬度约为单层DLC薄膜的两倍;多层膜中具有硬质TiB_2层和软质DLC层的交替结构,在摩擦过程中,硬层TiB_2起到良好的承载作用,软层DLC起到良好的润滑作用,使多层膜具有比单层DLC薄膜更低的摩擦因数。     

钛合金人工心脏瓣膜瓣环表面TiN/Ti多层膜的制备与性能

为了提高钛合金人工心脏瓣膜瓣环TiO_2表面改性层的性能,利用非平衡磁控溅射技术在人工心脏瓣膜瓣环表面制备了具有不同调制周期(44,70,100 nm)的TiN/Ti多层膜过渡层;采用XRD、SEM、显微硬度计及摩擦磨损试验机研究了薄膜的物相组成、横截面形貌、硬度和耐磨性。结果表明:TiN/Ti多层膜由Ti和TiN相组成,当调制周期为100 nm时,TiN/Ti薄膜呈现明显的多层结构,具有高硬度和良好耐磨性;人工心脏瓣膜瓣环表面各个位置TiN/Ti多层膜的相结构及性能相同,可望应用于人工心脏瓣膜瓣环的TiO_2表面改性层的过渡层。     

Tribology and oxidation behavior of TiN/AlN nano-multilayer films

In this study, a series of TiN/AlN nano-multilayer films were prepared using a new sputtering setup, which features a medium frequency (MF) twin unbalanced magnetron sputtering system (UBMS) and a DC balanced magnetron sputtering system (BMS). The MF (6.78 MHz) twin UBMS, which is a modification of single RF power source system, is a special design of this deposition machine. The UBMS was employed to deposit the AlN film, and the BMS the TiN film. The aim of this study was to obtain, through controlling the deposition conditions, a group of TiN/AlN nano-multilayer films with various periods (λ). Then a series of experiments were conducted to understand their wear and oxidation properties.The results revealed that through controlling of the deposition parameters, the TiN/AlN nano-multilayer films with λ ranging from 2.4 to 67.6 nm were obtained. At λ3.6 nm, the nano-multilayers had extremely high hardness and excellent adhesion. The oxidation tests found that the multilayers had obviously better anti-oxidation property, as compared with the single-layer TiN film. The high hardness and good oxidation resistance contributed to very good wear performance of the TiN/AlN nano-multilayer films.     

烧结助剂添加方式对AlN陶瓷力学性能的影响

通过直接添加与原位生成两种方式引入Y_2O_3作为烧结助剂,热压烧结制备了AlN陶瓷;研究了添加方式及添加量对AlN陶瓷显微结构和力学性能的影响。结果表明:原位生成烧结助剂的方式更有利于AlN陶瓷的致密化,特别是当原位生成的Y_2O_3质量分数为2%时,AlN陶瓷的相对密度达到99.0%,硬度为15.39GPa,抗弯强度为383.0MPa,均高于直接添加Y_2O_3的;同时可获得晶形完整、第二相含量少且大部分位于三叉晶界、晶粒间面-面接触的显微结构;随着原位生成烧结助剂添加量的增多,陶瓷的相对密度下降,在AlN晶界处出现大量第二相而导致陶瓷的硬度、抗弯强度等力学性能也下降。     

人牙釉质和合成羟基磷灰石力学性能的对比研究

鉴于人牙釉质由96%～97%质量比的羟基磷灰石构成,选用合成羟基磷灰石作为空白对照样,通过纳米压痕仪、SEM、EDX等考察和分析不同载荷下人牙釉质和合成羟基磷灰石的力学性能,初步分析人牙釉质内部微观结构对其力学性能的贡献。结果表明:在相同载荷作用下,人牙釉质的硬度和弹性模量低于合成羟基磷灰石,且压痕较深。牙釉质和合成羟基磷灰石的硬度和弹性模量均随载荷增大而降低,压痕深度随载荷增大而增大,其中,合成羟基磷灰石的硬度和弹性模量随载荷增大而降低的幅度略大于人牙釉质。可见,人牙釉质的力学性能与其内部微观结构密切相关。     

应用纳米压痕法测试类金刚石薄膜的力学性能

纳米压痕仪被称为材料机械性质微探针,它借助于加载-卸载过程中压痕对载荷和压入深度的敏感关系,使得测试始终在薄膜材料的弹性限度内,克服了维氏法和努氏法等传统方法引起压痕边缘模糊或者碎裂的缺点,从而正确地、可靠地测试出薄膜材料的硬度和弹性模量等纳米力学性能.试验用微波电子回旋共振等离子体增强化学气相沉积技术,在不同偏压条件下制备三种类金刚石薄膜(DLC膜),用纳米压痕仪测试不同载荷下薄膜的硬度和弹性模量值.试验结果表明,材料的纳米硬度和弹性模量随着载荷的增大而逐渐减小.     

Scratch hardness and mechanical property correlation for Mg/SiC and Mg/SiC/Ti metal–matrix composites

Scratch hardness results conducted on magnesium based metal–matrix composites using submicron SiC (4.8–15.4 wt%) and micron sized Ti (2.7 wt%) particulates are presented. These results are further correlated with composites' bulk mechanical properties such as the normal hardness, the elastic modulus and the yield strength. The data show that the scratch hardness correlates well with the normal hardness and the elastic modulus as all of these parameters increase with an increase in the weight percent of the reinforcing particulates. The scanning electron microscopic study reveals that the composites have greater tendency to form brittle cracks at the edges and wear debris in comparison to pure Mg. The addition of 2.7 wt% of Ti marginally increases the scratch resistance of the composites.     

Multipoint indentation for material identification in three-dimensional observation based on serial sectioning

Three-dimensional (3D) observations of internal structures are important for evaluating material properties. Serial sectioning with destructive processes is traditionally employed as a 3D observation method. Identifying the boundaries of elements in microscope images and measuring the mechanical properties of each element are required for the evaluation of the mechanical properties of composite materials. This study provides a system for measuring the local hardness and elastic modulus by conducting indentation tests during serial sectioning processes. An automatic serial sectioning observation was performed during a combination process of precision cutting in high-speed milling with a single-crystal diamond tool and microscopic observation. A Vickers indenter was attached to a tool spindle table, and indentation tests were conducted under a displacement control process at submicron spatial resolution. The indentation modulus was obtained by analyzing the force–displacement profile measured during the unload process. The scale effects relating to the indentation depth in the measurements of the indentation modulus were confirmed for an Al alloy sample measured in this system. This study focused on the identification of components by using hardness information measured under the same indentation depth on a two-dimensional flat surface after precision cutting of the material. Three types of metal wires (1 mm diameter) embedded in plastic resin were used in the experiment. The hardness distributions on the serial sectioning surfaces were measured, and the values measured at each wire area on 3D positions were used for the identification of their material properties. This serial sectioning observation creates a 3D microstructural model including not only microscopic images, but also hardness and elastic modulus information for the identification of components in the microscopic area.