复相陶瓷刀具材料设计的理论框架

建立了复相陶瓷刀具材料设计的理论框架,该框架主要包括设计要求,系统设计、组分设计、微观结构设计、工艺设计、材料制备以及材料应用等,提出在复相陶瓷刀具材料设计的理论框架中,应该把工件材料应用等,提出在复相陶瓷刀具材料设计的理论框架中,应该把工件材料视为一“独立相”,充分考虑它与刀具材料之间的化学相容性问题,实验证明该研究思路是正确的,它对于复相陶瓷刀具材料设计具有重要的应用价值。     

纳米复相陶瓷刀具材料的研究现状

纳米复相陶瓷刀具材料的研究成功有望从根本上解决陶瓷材料的脆性问题，比起传统刀具陶瓷刀具材料，它具有更高的抗弯强度、断裂韧度等力学性能。本文介绍纳米复相陶瓷的增韧补强机理；总结了现阶段以Al2O3、Si3N4、ZrO2和Ti（C、N）四种陶瓷为基体的纳米复相陶瓷刀具材料的显微结构和力学性能之间的关系，并且指出了纳米复相陶瓷刀具材料今后的研究方向。     

金属相在复相陶瓷刀具材料中体积含量的研究

依据陶瓷刀具材料晶粒的结构,建立了四种晶粒模型,通过理论计算,得出了金属相在陶瓷刀具材料中体积分数的合理取值范围(3.5%-13%);以3.6vol.%、5.1vol.%、6.6vol.%、8.1vol.%的Ni作为金属粘结相,制备了TiB2-TiC-WC复相陶瓷刀具材料,用扫描电镜分析了材料的微观结构,陶瓷晶粒呈六棱体状或方体,金属相包覆在陶瓷晶粒周围,并且当Ni的含量为5.1vol.%时,可以获得力学性能优良的复相陶瓷刀具材料。     

基于ANSYS的纳米复相陶瓷木工刀具虚拟优化设计

提出将纳米复相陶瓷刀具应用到木质材料加工中.首先证明了利用ANSYS的Solid95单元所构建的三维模型对木材切削过程进行有限元分析的可行性;然后通过ANSYS程序计算不同纳米复相陶瓷刀具前角所对应的最大有效应力,并推断最优前角的角度值;最后通过实验进行比较,证明优化结果与实验结果基本一致.利用该方法可对木材切削过程进行分析及对刀具进行优化设计.另外,还通过实验证明了纳米复相陶瓷刀具比普通硬质合金刀具耐用度高,适合进行木质材料加工.     

Al2O3陶瓷材料的摩擦学研究进展

氧化铝陶瓷刀具材料具有硬度高、耐磨性好、高温性能优良、抗黏结和抗扩散能力强、化学稳定性好等特点,广泛应用于高速切削和切削难加工材料领域。从陶瓷材料晶粒尺寸与摩擦学性能相关性、复相氧化铝陶瓷材料的摩擦学性能和氧化铝陶瓷的磨损机制3个方面,综述氧化铝陶瓷材料摩擦学研究进展,以期为新型高品质氧化铝陶瓷刀具材料的开发提供帮助。细化晶粒和组分复合化是提高陶瓷材料的强度和断裂韧性,进而提升其摩擦学性能的有效途径,但目前氧化铝陶瓷摩擦学研究主要是基于晶粒尺寸为600 nm以上的单相陶瓷和基体晶粒尺寸为1μm左右的复相陶瓷材料,对纳米/超细晶(500 nm以下)氧化铝陶瓷材料的研究是未来的研究方向。     

新型陶瓷切削刀具

陶瓷是由金属氧化物或金属氮化物组成,但不含金属无机材料。早在1905所就有人用氧化铝(Al_2O_3)做切削刀具,但由于当时的陶瓷材料脆性大、强度低、品质不均匀,加上所用机床的刚性差、功率小,因而使用效果不好。近年来,随着陶瓷生产工艺的改进,开发出了强度较高、均匀性较好的陶瓷刀具材料,并且机床的性能有了很大的改善,从而使陶瓷刀具的应用越来越广泛。陶瓷刀具的性能还将通过下述技术得到进一步的提高。 1.表面处理一采用化学气相沉淀或其他方法在陶瓷表面涂复各种适当的涂层; 2.相转变-用化学方法添加不同材料,以实现相转变而强化陶瓷刀具材料。陶瓷刀具有以下主要优点: 1.陶瓷刀具化学稳定性好,抗磨损能力强,能长时间保证刀刃锋锐,使刀具在较长时间内维持加工的     

三维三相纳米陶瓷刀具材料微观组织的相场法模拟

建立了添加两种纳米颗粒的三相陶瓷刀具材料微观组织的相场法模拟模型,改进了三维尺度下的现有模拟算法,提出了一种更为有效的模拟算法,成功模拟了200×200×200单位的三相复合陶瓷刀具材料的微观组织演化过程,提高了计算效率。分别模拟了单相材料与三相纳米陶瓷刀具材料的微观组织演化过程。结果表明,添加纳米颗粒的三相纳米陶瓷刀具材料的晶粒尺寸分布峰值较小,说明纳米颗粒对晶界的钉扎效果明显,起到了较好的细化基体相晶粒的作用。     

陶瓷刀具的发展及其应用

切削加工是先进制造技术的最重要的基础技术。现代陶瓷刀具具有高的耐热性、高的硬度与耐磨性能和优良的化学稳定性等独特的优点,它是先进制造技术强有力的武器,将成为21世纪的最重要的刀具材料之一。陶瓷刀具具有很高的硬度、耐磨性能及良好的高温力学性能,与金属的亲合力小,不易与金属产生粘结,并且化学温度性好。因此,陶瓷刀具可以加工传统刀具难以加工或根本不能加工的超硬材料,实现以车代磨,从而可以免除退火、简化工艺、大幅度地节省工时和电力;陶瓷刀具的最佳切削速度可以比硬     

Al_2O_3-TiC复相陶瓷刀具干切削高强度钢40CrNiMoA的试验研究

用Al2O3-TiC复相陶瓷刀具对高强度钢40CrNiMoA进行了干车削试验,研究分析了精加工条件下不同切削用量对切削力、工件表面质量以及切屑形态和刀具磨损的影响。结果表明用Al2O3-TiC复相陶瓷刀具在较高速度下干车削40CrNiMoA时可获得良好的表面加工质量,并且刀具磨损量较小,可满足40CrNiMoA精加工的要求。     

气氛烧结氮化硅陶瓷刀具的切削性能研究

本文主要介绍气氛烧结氮化硅(Si_3N_4)陶瓷刀具材料的制造工艺特点及物理机械性能,分析用该陶瓷刀具粗加工、半精加工铸铁材料时的切削机理及刀具切削性能,并阐述用该陶瓷刀具切削铝合金和淬火钢材料时的特性,以表明它具有广泛的应用前景。文中指出合理使用此种刀具的几个问题,可供推广使用时参考.     

Workpiece Compatibility of Ceramic Cutting Tools

It is now well known that certain types of cemented carbides give excellent results when used to cut cast irons but poor results when used to cut steels and vice versa. This relative ability of a given tool material to perform well when cutting a given workpiece material is referred to here as compatibility.

Ceramic metal cutting tools have been in use in machining metals such a short time that it is not yet generally known on which materials these tools can be used to best advantage. In this report the performance of ceramic and cemented carbide tools is compared when machining a wide variety of metals. It is found that there are certain metals for which either the surface chemical or thermal characteristics of ceramic tools are particularly advantageous.

The report is concluded by a table which lists a large number of ferrous and nonferrous metals in order of decreasing compatibility with aluminum oxide tools.     

Evaluation of the Machinability of Nickel-Base,Inconel 718, Alloy with Nano-Ceramic Cutting Tools

The machinability of difficult-to-cut aerospace alloys can be enhanced by the rapid development of cutting tool materials that can withstand machining at high-speed conditions. The performance of nano-grain size ceramic tool materials were evaluated when machining nickel base, Inconel 718, in terms of tool life, tool failure modes and wear mechanisms as well as component forces generated under different roughing conditions. Comparison tests were carried out with commercially available ceramic tool materials of micron-grain composition.

The test results show that the micron grain size commercially available tool materials generally gave the longest tool life. The dominant failure mode is nose wear, while some of the nano-ceramic tools were rejected mainly due to chipping at the cutting edge. This suggests that physical properties and mechanical stability of the cutting edge of the ceramic tools influence their overall performance. It is also evident that chemical compositions of the tool materials played a significant role in their failure. The alumina base ceramics are more susceptible to premature fracture than the silicon nitride base ceramics with higher fracture toughness.     

金属包覆型复合粉末及其在工程材料中的应用

金属包覆型复合粉末是一种壳-核状结构的粉末,兼有金属与非金属的性质,因而在众多领域得到广泛应用。在简述这种粉末制备方法的基础上,对化学镀法制备的粉末在陶瓷刀具、金刚石磨具、碳刷电极、摩擦片、电触头以及金属基复合材料、热喷涂粉末、减震材料等工程材料方面的研究现状进行了综述,并展望了其发展方向。     

先进陶瓷刀具材料的破损性能

研究了稀土补强Ａｌ２Ｏ３／（Ｗ,Ｔｉ）Ｃ陶瓷刀具材料的破损性能,发现在断续切削淬硬４５钢时,该刀具材料具有较镐的抗破损性能,其抗破损性能比相应不含稀土的Ａｌ２Ｏ３／（Ｗ,Ｔｉ）Ｃ陶瓷刀具材料提高约２０％,在不同的切削条件下,疲劳裂纹和热裂纹是造成刀具材料失效的主要原因。     

Experimental study on trepanning drilling of the ceramic composite armor using a sintering diamond tool

Laminated ceramic composite armors made of engineering ceramics, fiber-enforced composite, and lightweight alloy are expected to be used widely in armor protection area. However, secondary machining is still a problem for the distinct properties of composing materials, and up to now, few reports can be found out about machining technology. In this work, an experimental study on drilling a typical laminated ceramic composite armor by using a special sintering diamond thinwall trepanning tool has been carried out deeply. To improve the machining efficiency, process parameters including the spindle speed and the axial force have been optimized through drilling experiments. Moreover, the three phases of the whole drilling process of the typical ceramic composite armor is proposed, and the machining mechanism and chip forms in each phase have been analyzed. Also, diamond tool skidding phenomena whether at hole exit or during drilling middle engineering ceramics have been explored, and the skidding mechanisms are presented. In addition, the surface quality of a hole wall machined has been studied, and an advisable measure is given. Results achieved in this paper can provide a technical base for diamond trepanning tool drilling similar laminated ceramic composite armors.     

Al2O3/TiC系梯度功能陶瓷刀具材料的设计

提出了对称型双向分布的梯度功能陶瓷刀具材料的设计模型。根据陶瓷刀具切削时刀楔内的应力分布规律,对不同组成分布情况下梯度材料制备过程中的残余热应力进行有限元计算,以残余应力部分缓解切削过程中的外载应力为目标来设计组成分布。提出了优化设计原则。     

Wear and Tribological Performance of Different Ceramic Tools in Dry High Speed Machining of Ni-Co-Cr Precipitation Hardenable Aerospace Superalloy

Tool wear is an important machinability criterion. To reduce total machining costs, this study demonstrates the wear and tribological performance of four ceramic tools in dry high-speed turning of Ni-Co-Cr precipitation hardenable superalloy (Inconel 100). Wear of the tool materials and the structural and phase transformations at the tool–chip interface were investigated. Results obtained reveal that SiAlON ceramic outperformed other ceramic tool materials at different cutting speeds due to the formation of a large amount of mullite tribofilms on the tool face, which serve as a thermal barrier layer. Alumina ceramic with the addition of ZrO₂ can be recommended for machining Inconel 100 at speeds above 150 m/min due to its ability to form thermal barrier ZrO₂ tribofilms, which decrease the coefficient of friction at the tool–chip interface. Mixed alumina and an alumina matrix reinforced with SiC_w were found to be unsuitable for machining age-hardened Inconel 100 superalloy.