利用人工神经网络方法开发Al2O3/TiN系复相陶瓷刀具材料

复相陶瓷刀具材料应用前景广阔。本文提出了利用人工神经网络方法辅助开发复相陶瓷刀具材料，基于BP算法，建立了预测颗粒增韧复相陶瓷刀具材料各组分体积百分含量的预测模型。实际开发了Al2O3/TiN系复相陶瓷刀具材料，材料的力学性能满足要求。     

基于抗破损性能与可靠性的复相陶瓷刀具材料的组分设计模型

提出陶瓷刀具抗破损系数的概念,用以不征刀具的抗破损性能。建立了基于抗破损性能的复相陶瓷刀具材料的组分设计模型,并以Ａ１２Ｏ３／ＳｉＣ／（Ｗ,Ｔｉ）Ｃ和Ａ１２／Ｏ３ＳｉＣ／Ｔｉ（Ｃ,Ｎ）陶瓷刀具材料组分系统为例,进行了相应的优化设计。探讨了陶瓷刀具可靠性与刀具材料组分之间的关系,认为建立二者之间的间接关系可行的。以此为基础,就能最终实现基中靠性的复相陶瓷刀具材料的组分设计。     

陶瓷刀具材料的现状与发展

本文阐述了陶瓷刀具材料的发展现状 ,着重论述了氧化铝系陶瓷和氮化硅系陶瓷材料技术。对陶瓷刀具材料的发展趋势进行了综述。指出超微粉刀具、复相陶瓷刀具、涂层刀具及金属陶瓷是陶瓷刀具材料的研究方向。     

物理和化学相容性及其对陶瓷刀具材料JX-2-1力学性能的影响

本文首先研究了新型复相陶瓷刀具材料JX-2-I的物理和化学相容性;其次研究了复合材料相容性对刀具材料力学性能的影响,结果表明,在JX-2-I材料中,各组成相之间具有较好的物理相容性和化学相容性,这有利于改善陶瓷刀具材料的性能。     

机床用Al_2O_3/TiB_2复相陶瓷刀具材料的研究

以α-Al2O3和TiB2为主要原料,采用真空热压烧结工艺制备机床用Al2O3/TiB2复相陶瓷刀具材料。测试和分析了烧结样品的相对密度、弯曲强度、断裂韧性、硬度值、相组成以及显微结构。结果表明,当α-Al2O3添加量为75 wt%,微米TiB2添加量为20 wt%时,所制备的Al2O3/TiB2复相陶瓷刀具材料性能最佳,其相对密度值为98.8%,弯曲强度为606.25 MPa,断裂韧性为4.85 MPa·m1/2,硬度值为26.55 GPa。最佳样品的主晶相为刚玉(Al2O3)和硼化钛(TiB2),次要晶相为氧化钇(Y2O3)。     

可加工BN/B_4C复相陶瓷的制备与其抗热震性能

采用热压烧结工艺制备了BN/B4C微米复相陶瓷和BN/B4C纳米复相陶瓷。由淬水法测试了单相B4C陶瓷,BN/B4C微米复相陶瓷和BN/B4C纳米复相陶瓷的抗热震性能,用三点弯曲法测试了热震后样品的抗弯强度。结果表明:BN/B4C微米复相陶瓷和BN/B4C纳米复相陶瓷的抗热震性能明显高于单相B4C陶瓷的抗热震性能,而且BN/B4C纳米复相陶瓷的抗热震性能明显高于BN/B4C微米复相陶瓷的抗热震性能。BN/B4C微米复相陶瓷和BN/B4C纳米复相陶瓷具有良好的抗热震性能主要是由于具有较高的抗弯强度和较低的弹性模量;同时BN/B4C复相陶瓷中的BN/B4C弱界面和层状结构的h-BN晶粒能够显著提高复相陶瓷的抗热震性能。     

硅液相浸渍反应制备TiC/SiC和TiN/SiC复相陶瓷

以滤纸、酚醛树脂和氧化钛为原料,经过模压成型、固化、碳化及不同条件下渗硅制备了TiC/SiC和TiN/SiC复相陶瓷。通过X射线衍射和扫描电子显微镜研究了TiC/SiC和TiN/SiC复相陶瓷的微观结构和物相组成,测量了复相陶瓷的弯曲强度和断裂韧性。结果表明:真空条件下液态渗硅获得的TiC/SiC复相陶瓷具有多孔的微观结构,其弯曲强度和断裂韧性较小。氮气气氛下液态渗硅制备的TiN/SiC复相陶瓷结构致密,有较高的弯曲强度和断裂韧性。不同反应生成的TiC,TiN陶瓷颗粒对液态硅的润湿性不同,使得生成的复相陶瓷具有不同的微观结构。TiN/SiC复相陶瓷中TiN颗粒的引入,在基体与第二相颗粒间的界面上产生拉应力和压应力,使达到这一区域的裂纹偏转,从而获得增韧效果。     

莫来石/刚玉复相陶瓷热断裂特性研究

通过调整复相陶瓷中颗粒相的组成与级配,利用引入的热膨胀失配机制,控制莫来石/刚玉复相陶瓷显微结构,改善高温复相陶瓷热稳定性,着重研究了莫来石/刚玉复相陶瓷的热断裂特性.研究表明,全部采用莫来石颗粒相时,由于柱状莫来石颗粒极易发生热冲击穿晶断裂,且热膨胀失配导致的微裂纹较长,密度较小,故复相陶瓷热稳定性较差;全部采用刚玉颗粒相时,虽然基质相裂纹扩展至刚玉颗粒表面时穿晶断裂与沿晶的裂纹扩展同时发生,有利于改善复相陶瓷热稳定性,但由于热膨胀失配过度,未经热冲击时已产生宏观裂纹,故热稳定性最差.而采用莫来石/刚玉复合颗粒相,相比例为75/25制备的复相陶瓷试样,热膨胀失配形成的微裂纹较短,密度较大,其热稳定性最优.     

氧化铝/氮化铝陶瓷显微组织研究

氮化铝具有良好的热学、电学和机械等性能,是理想的电子封装材料和高性能陶瓷基板材料.本文研究了AlN加入量和烧结温度对Al2O3/AlN复相陶瓷相组成和显微组织的影响.结果表明该陶瓷在1400～ 1550℃烧结时,AlN被部分保留,少量氧原子进入AlN晶格,烧结生成4种铅锌矿结构新相,有利于提高复相陶瓷热导率;氮化铝含量和烧结温度的提高,有利于形成大尺寸晶粒.     

石墨烯/Al_2O_3复相陶瓷材料的制备研究

采用Hummers法制备了石墨烯。利用复相陶瓷掺杂理论,研究了不同含量氧化石墨烯、不同烧结工艺对陶瓷晶粒的各向异性生长及材料致密度的影响。利用真空热压烧结法制备了复相Al_2O_3陶瓷,通过硬度测试、摩擦磨损测试、密度测试、SEM、XRD、拉曼散射等分析方法,对样品进行了成分分析以及端口形貌观察、显微组织观察,对影响复相Al_2O_3陶瓷制备的各种因素进行了试验研究与讨论。     

Microstructure design and preparation of Al2O3/TiC/TiN micro-nano-composite ceramic tool materials based on properties prediction with finite element method

The objective of this paper was to improve the accuracy of semi-empirical method used to design ceramic cutting tool materials. The mechanical properties were predicted by employing finite element model of material microstructure, so as to design microstructure and prepare new ceramic materials. Based on the Voronoi and randomness method, the microstructure model representing the complexity and randomness of micro-nano-composite ceramic material microstructure was established. Combining the representative volume element (RVE) of ceramic material microstructure with mechanical tests, the simulations of mechanical tests were conducted to acquire the flexure strength, fracture toughness and hardness of materials. The microstructure models with various parameters were designed and the material properties were predicted to determine the optimal microstructure parameters. Then, The ceramic cutting tool materials possessing the optimal microstructure parameters were developed for machining ultra-high strength steels. The results showed that the mechanical properties of ceramic materials first improved and then declined as the nano-scale TiC volume fraction increased. To obtain the best comprehensive mechanical properties, the contents of micro-scale TiN, TiC and nano-scale TiC were set as 20%, 10% and 10%, respectively. The prepared ceramic materials possessed the flexure strength of 881.4 MPa, the fracture toughness of 7.8 MPa m^1/2, and the Vickers hardness of 20.8 GPa. This research is beneficial to the development of cutting tool design theory and the improvement of the tool life.     

现代陶瓷刀具材料的发展

刀具材料的发展经历了工具钢、高速钢、金属陶瓷、陶瓷和超硬材料五个阶段,精密加工脆性和高硬度的材料促进了刀具材料的不断发展。     

硬质合金粉末表面涂层陶瓷的材料

利用溶胶－凝胶法在ＴｉＣ粉末,（Ｗ,Ｔｉ）粉末表面涂层Ａｌ２Ｏ３陶瓷,通过热压烧结制得了两种新型涂层的刀具材料（ＦＴＣ１和ＦＴＣ２）,粉末涂层材料ＦＴＣ１和ＦＴＣ２的力学性能满足刀具材料的使用要求。利用扫描电镜观察发现基体粉末表面较均匀地涂覆了一层α－Ａｌ２Ｏ３陶瓷,并对材料的力学性能和微观结构进行了分析。     

技术创新助推新型陶瓷刀具在机加工中的应用优势凸显

随着新技术革命的发展,要求不断提高切削加工生产率和降低生产成本,特别是数控机床的发展,要求开发比硬质合金刀具切速更高、更耐磨的新型刀具。针对新型陶瓷切削刀具的应用前景广阔,分析了切削刀具材料的种类及其特点,研究了新型陶瓷切削刀具的性能突显,介绍了新型陶瓷切削刀具运用实例,提出了陶瓷切削刀具材料的研发应用方向。     

复相陶瓷材料的设计原则

根据陶瓷材料在使用上的性能要求，设计和确定材料的组成、显微结构和工艺，是陶瓷材料研究的进步。陶瓷材料向多相方向发展，为陶瓷材料的晚思考余地。本文阐述了复相陶瓷瓣设计原则，显微结构的设计，不同相之间的化学共存，不同相之间的物理匹配。     

Performance of Si3N4/(W,Ti)C graded ceramic tool in high-speed turning iron-based superalloys

A Si₃N₄/(W, Ti)C graded nano-composite ceramic tool was fabricated and its performance in high speed turning iron-based alloys GH2132 was investigated compared with homogeneous and commercial ceramic tools. The chip morphology, cutting forces, cutting temperature, tool life and failure mechanisms and machined surface roughness were recorded and analyzed. The results showed that with the increasing cutting speed the resultant cutting force shows a tendency to first increase and then decrease while the cutting temperature increases gradually. Straight continuous chips, bending continuous chips, twist continuous chips and snarled chips form in turn. Saw-tooth chips tend to form when the cutting speed is more than 200?m/min. The graded tool shows longer tool life especially at the cutting speed of 150 and 200?m/min compared with the homogenous and commercial ceramic tools. Tool failure modes mainly include grooving on the rake face, notching on the flank face, abrasion and adhesion. The grooving on the rake face tends to decrease while notching on the flank face tends to increase as cutting speed increases. Surface roughness of the machined iron-based super-alloys is relatively high due to the serious adhesion. Better surface roughness can be got using the graded tool.     

Cutting performance of microwave-sintered sub-crystal Al2O3/SiC ceramic tool in dry cutting of hardened steel

Tool life and failure mechanisms of a microwave-sintered sub-crystal Al₂O₃/SiC ceramic tool (AS) in dry turning hardened steel were studied. The AS tool with plane face shows better cutting performance and wear resistance than the commercial ceramic tool SW500 and cemented carbide tool YG8 at both low and high cutting speeds. It's suitable for dry cutting at high speed (210–270 m/min), the cutting distance is 5–8 times longer than that of other two tools. The results indicate that the ceramic tool fabricated by this pressureless sintering technology can satisfy the requirements of high-speed machining. Wear forms of AS tool at low cutting speed are slight crater wear and groove wear, which were mainly caused by abrasion. At high cutting speed, tool failure forms are cater wear, groove wear and slight chipping caused by severe abrasion and adhesion.     

利用人工神经网络预测复相陶瓷材料组分含量的研究

根据人工神经网络（ANN）的BP(back propagation）算法,预测复相陶瓷各组分的体积分数的神经网络模型,模型由三层神经元组成,分别为输入层、隐含层和输出层用以模拟人脑的结构,输入层参数由两部分组成,一部分为抗弯强度、硬度和断裂韧性等力学性能,另一部分包括相应各组分的弹性模量和热膨胀系数,以用来辨识不同的材料系统,输出层参数是复相陶瓷中各组分的体积分数,只要训练样本值足够精确,预测模型就能够预测已有的陶瓷系统的组分含量,同时,模型能够预估未知材料系统的组分含量。计算证明,模型的容错性较好,因此对开发新型复相陶瓷非常有益。