梯度功能陶瓷刀具材料的残余应力设计及制备

根据陶瓷刀具切割时刀楔内的应力分布规律及刀具损坏机理的分析，首次提出以陶瓷刀具材料的组成分布进行设计以及梯度的模型，通过对不同组成分布的刀具材料制备过程中的残余应力及刀具切削过程中的热应力，机械应力进行模拟，以残余应力与外加应力部分抵消为目标优化设计了梯度组成分布，按设计结果，采用粉末铺填－热压烧结工艺研制成功Ａｌ２Ｏ３／ＴｉＣ系梯度功能陶瓷刀具材料。     

Sialon-Si3N4系梯度纳米复合陶瓷刀具材料的设计及制备

根据对切削过程中陶瓷刀具温度及应力分布规律的研究,提出对陶瓷刀具材料的组成分布和微观结构进行设计以形成梯度的模型.通过调节TiC0.7N0.3含量,使材料在制备的冷却过程中在材料表层形成残余压应力.纳米Si3N4颗粒的加入可提高材料的微观性能;而合理的梯度结构设计提高了材料的宏观性能.采用粉末铺填热压烧结工艺制备出si...     

PSZ—Mo系梯度功能材料的热应力缓和设计与制备

对ＰＳＺ－Ｍｏ系梯度功能材料在制备过程中的热应力缓和性能进行了优化设计，用有限元方法解析了ＰＳＺ－Ｍｏ系两层叠层材料（即非梯度功能材料）在制备过程中的热应力分布情况。同时解析了ＰＳＺ－Ｍｏ系ＦＧＭ在制备过程中的热应力分布及缓和规律。揭示了ＰＳＺ－Ｍｏ系ＦＧＭ在制备过程中的热应力大小与组成分布形状指数Ｐ的关系，对所研究的体系通过热应力缓和最佳时的Ｐ值，同时，对ＦＧＭ的制备工艺进行了研究，用粉末法分别     

Ni／Ni3Al—TiC系梯度功能材料的热应力缓和特性设计

本文选择Ｎｉ／ＮｉＡｌ－ＴｉＣ体系的ＦＧＭ，对其在制备过程中的残余絷应力进行了计算机有限元模拟。在综合考虑热应力最小，应力强度比值最小以及纯ＴｉＣ侧应力状态等因素的基础上，完成了ＦＧＭ体系的热应力缓和特性设计，得到组成分布指数Ｐ＝１．６的最佳设计结果。     

PSZ－Mo系梯度功能材料的热应力缓和设计与制备

对ＰＳＺ－Ｍｏ系梯度功能材料（ｆｕｎｃｔｉｏｎａｌｌｙｇｒａｄｉｅｎｔｍａｔｅｒｉａｌｓ简称ＦＧＭ）在制备过程中的热应力缓和性能进行了优化设计，用有限元方法解析了ＰＳＺ－Ｍｏ系两层叠层材料（即非梯度功能材料）在制备过程中的热应力分布情况。同时解析了ＰＳＺ－Ｍｏ系ＦＧＭ在制备过程中的热应力分布及缓和规律。揭示了ＰＳＺ－Ｍｏ系ＦＧＭ在制备过程中的热应力大小与组成分布形状指数Ｐ的关系，对所研究的体系通过热应力解析，得到制备中热应力缓和最佳时的Ｐ值，同时，对ＦＧＭ的制备工艺进行了研究，用粉末法分别制备出２４ｍｍ×５．６ｍｍ和３０ｍｍ×５ｍｍ完整的ＦＧＭ试样。     

Al2O3/TiC纳米陶瓷刀具材料的抗热震性能及断裂机理研究

用强度衰减法对Al2O3／TiC纳米陶瓷刀具材料的抗热震性能进行了详细的研究。热震实验表明该种材料的临界热震温差为340℃。当温差达到350℃时，强度有明显的下降。与微米级的材料相比，纳米材料的抗热震性能反而有所降低。通过对热震后试样表面的显微观察和表面热应力的估算发现，材料在烧结后冷却过程和热震过程中产生的热应力导致试样表面产生裂纹，从而导致了材料强度的下降。     

Ni/Ni_3Al-TiC系梯度功能材料的组成结构设计与制备

选择Ｎｉ／Ｎｉ３ＡｌＴｉＣ体系的ＦＧＭ，对其在制备过程中的残余热应力进行了计算机有限元模拟。在综合考虑热应力最小、热应力发生位置以及纯ＴｉＣ侧应力状态等因素的基础上，完成了ＦＧＭ的组成结构设计与优化，得到了组成分布指数Ｐ＝１．６的最佳设计结果。按此设计结果，采用热压烧结工艺，制备出完整的、无宏观缺陷的Ｎｉ／Ｎｉ３ＡｌＴｉＣ系ＦＧＭ样品。     

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。     

TiC／Ni3Al系梯度功能材料在稳定状态下的隔热应力及其组成分布优化

通过实验方法，测定了ＴｉＣ／Ｎｉ３Ａｌ复合材料的诸物性参数，在此基础上，对于ＴｉＣ／Ｎｉ３Ａｌ系梯度材料（ＦＧＭ）在稳定状态下产生的隔热应力，利用有限元方法进行了热弹性模型下的三维解析，在考虑热应力最小，比应力最小以及ＴｉＣ侧应力状态等因素之后，对圆反状ＴｉＣ／Ｎｉ３Ａｌ系梯度材料的组成分布进行了优化。     

新型刀具材料——陶瓷

介绍了陶瓷刀具材料的种类和发展过程、陶瓷刀具材料的性能和应用范围，并列入一些切削试验数据。     

陶瓷涂层三明治板的抗热震性

采用解析法研究了第3类边界条件下双面陶瓷涂层三明治板的瞬态温度场及瞬态热应力场.对不同Biot模数的热冲击过程中,Al2O3涂层/硬质合金(WC-8%Co,质量分数)基体/Al2O3涂层三明治板的瞬态热应力进行了数值计算.分析了涂层/基体厚度比、涂层与基体热-物理性能匹配对陶瓷涂层三明治板表面热应力峰值的影响.结果表明:陶瓷涂层三明治板的基体的热导率、线膨胀系数和弹性模量应高于涂层,这样可以降低其表面热应力,获得高抗热震性陶瓷涂层三明治板.此外,涂层厚度应尽可能小,以利于改善涂层的抗热震性.     

Machining performance of phase transformation toughened alumina and partially stabilised zirconia composite cutting tools

Phase transformation toughened zirconia (TTZ) doped with yttria or ceria has excellent properties such as higher order fracture toughness, thermal shock resistance and moderate hardness. With these qualities, they are able to exhibit machining performance comparable to cold-compacted Al₂O₃ cutting tools. With an addition of 20% aluminium oxide to TTZ, i.e. the composites of alumina and partially stabilised zirconia (PSZ) exhibit improved toughness, enhanced thermal shock resistance and hardness. The alumina and PSZ composite ceramic tools exhibit cutting performance better than TTZ tools and comparable to zirconia toughened alumina tools.     

对称型梯度功能陶瓷材料抗热震性的研究

通过水淬实验并结合热冲击过程瞬态热应力场的计算，研究了Al2O3/W(W,Ti）C系列对型梯度功能陶瓷材料的抗热震性能。结果表明，采用合理的梯度组成分布规律可提高陶瓷材料的抗热震性。     

Cutting performance and wear mechanisms of the graphene-reinforced Al2O3-WC-TiC composite ceramic tool in turning hardened 40Cr steel

The Al₂O₃-WC-TiC-graphene composite ceramic tool (AWTG0.5) fabricated by two-step hot pressing was used to continuously turn the hardened 40Cr steel at different cutting speeds, and its cutting performance and wear mechanisms were compared with the homemade graphene-free AWTG0 ceramic tool and the commercial ceramic tools SG4 and LT55. The cutting performance of the AWTG0.5 tool was significantly better than that of the AWTG0, SG4 and LT55 tools. The contributions of graphene to the mechanical properties, lubricating properties and thermal conductivity of the AWTG0.5 tool were responsible for its higher cutting performance. The main wear mechanisms of the AWTG0.5 tool were adhesive wear and abrasive wear. In addition, it was also found that the anti-friction and wear resistance performances of the AWTG0.5 tool were superior to those of the other three tools. Its good anti-friction and wear resistance performances could be attributed to the formation of a self-lubricating layer induced by graphene pull-out.     

新型陶瓷刀具的机械应力分析

计算了梯度功能陶瓷刀具和普通陶瓷刀具内的最大Mises应力，最大剪应力和最大拉应力。在低速切削时梯度功能陶瓷和普通陶瓷刀具内机械应力场基本相同，前刀面的破损形式基本一样。     

低碳经济驱动新型陶瓷材料行业的未来

新型陶瓷材料具有高强、高硬、耐腐蚀、耐高温等特性。近些年来,在开发新能源和有效利用石油能源的呼声中,发达国家相继掀起了新型陶瓷材料研究开发的热潮。针对新型陶瓷材料的独特性能,综述了工程陶瓷材料用途广泛和特殊性能的功能陶瓷材料广阔应用前景;以及陶瓷基复合材料具有广泛的发展趋势;介绍了广泛应用于工程领域的陶瓷阀门材料和切削性能优良的新型陶瓷刀具;同时指出了陶瓷材料产业的应用开发趋势。     

低碳经济驱动新型陶瓷材料行业的未来

新型陶瓷材料具有高强度、高硬度、耐腐蚀、耐高温等特性。近些年来,在开发新能源和有效利用石油能源的呼声中,发达国家相继掀起了新型陶瓷材料研究开发的热潮。针对新型陶瓷材料的独特性能,综述了工程陶瓷材料用途广泛和功能陶瓷材料的应用前景,以及陶瓷基复合材料的发展趋势;介绍了广泛应用于工程领域的陶瓷阀门材料和切削性能优良的新型陶瓷刀具,同时指出了陶瓷材料产业的应用开发趋势。     

髋关节整体替代陶瓷材料

许多材料在医学领域应用广泛,例如,整体替换硬组织或软组织的元件(如骨盆、骨头、关节、植牙等)、修补、诊断或矫正仪器(如起搏器、心脏阀等)。这些材料不仅要有好的力学性能,还要保持长期稳定,不能与人体相排斥。由于陶瓷材料在生理环境中具有强度高、生物相容性强和稳定性好的优点,人们研究用陶瓷材料替换骨骼。从20 世纪70 年代起,欧洲人用陶瓷组件置换整个髋关节。这些组件主要由氧化铝和氧化锆单体制成。然而,在有水环境中,氧化锆会发生低温降解。目前人们的研究重点在于提高陶瓷组件的强度和耐磨性,同时缩小其尺寸并延长其使用寿命。研究中使用的材料是氧化锆增韧的氧化铝复合陶瓷和其它氧化铝复合陶瓷,不再是单体陶瓷。另外,还可以使用氧化铝和氧化锆功能梯度复合材料。该梯度材料可以利用电泳沉积法(EPD)制得,其表面为纯氧化铝,中心部分为均匀的氧化铝、氧化锆复合材料,中间过渡部分是呈连续梯度渐变的氧化铝、氧化锆复合材料,烧成后会产生剩余热应力。设计这样的梯度结构是为了使复合材料具有最大表面压应力和最小内部张应力,与纯氧化铝组件相比,提高了强度和耐磨性。     

Cutting performance and wear mechanism of TiB2-B4C ceramic cutting tools in high speed turning of Ti6Al4V alloy

TiB₂–20vol%B₄C (TB20) and TiB₂–80vol%B₄C (TB80) ceramic cutting tool materials were prepared by hot pressing, and then tested in turning of Ti6Al4V alloy with various cutting parameters. The tool life and wear mechanism of TB20 and TB80 were studied and compared with a commercial grade tungsten carbide tool (WO). The results of turning showed that effective cutting length of TB20 was about one third longer than that of TB80 and WO. Among the three tools, the increment of cutting temperature measured for TB20 was the lowest as flank wear increased from 0 to 600?µm. Analysis showed that dominant wear mechanism was adhesive wear in all of the three tools tested, while chipping was also observed in TB80 and temperature deterioration in WO. In addition, the TB20 exhibited a much better integrity of cutting edge after flank wear reaching 600?µm, due to its higher toughness than TB80 and higher thermal resistance than WO, respectively. The adhesive layers of work-piece material on the rake and flank faces of both TB20 and TB80 were much thinner than that of WO, which suggested a lower adhesive wear rate in TiB₂-B₄C cutting tools. The high wear resistance of TiB₂-B₄C cutting tools is attributed to higher thermal resistance, higher hardness, and lower chemical affinity with titanium as compared with tungsten carbides, which makes them very promising materials for high speed machining of titanium alloys.     

Ceramic dies selection for electrical resistance sintering of metallic materials

Processing metallic powders by electrical resistance sintering requires the use of insulating ceramics dies. Selecting the appropriate ceramic material according to the electrical, thermal and mechanical properties is a need. Dies produced with several ceramic materials have been tested during the production of cemented carbide in order to check their behaviour in the process and final product properties. Tialite/mullite, zircon/mullite, zirconium phosphate based ceramic, yttria-stabilized zirconia and sialon, in most cases with modified compositions and shaping processes in order to achieve a high density, have been tested. Dry powder processing by cold isostatic pressing and furnace sintering resulted to be the better process for dies production. The effect of die properties on the produced cemented carbide, and the behaviour and life of the die during the production have been analysed. Very smooth die surface increases the number of cycles withstood during metallic parts production, because of lower extraction stresses, as checked for sialon dies. Zirconium phosphate based dies, with low thermal conductivity, show the most densified hard metal parts surface.