【作者】 费玉环；

【导师】 黄传真；

【作者基本信息】 山东大学 ， 机械制造及其自动化， 2012， 博士

【摘要】 本文设计并研制了新型氧化铝基陶瓷刀具材料,研究了材料组分、烧结温度和保温时间对氧化铝基陶瓷刀具材料物相组成、微观组织和力学性能的影响,研究了新型氧化铝陶瓷刀具的切削性能。提出了氧化铝基新型陶瓷刀具材料的设计方案。选取微米Al203作为陶瓷刀具的基体材料,微米TiC、微米TiN和纳米TiN为添加相,MgO为烧结助剂,Ni和Mo为金属粘结剂,制备了四类氧化铝基陶瓷刀具材料,即Al203-TiNn陶瓷刀具材料(AN体系)、Al203-TiNn-TiNμ陶瓷刀具材料(ANU体系)、Al203-TiC-TiNμ陶瓷刀具材料(ACU体系)和Al203-TiC-TiNμ-TiNn陶瓷刀具材料(ACUN体系)。研究了陶瓷刀具材料物相组成及其对力学性能的影响。结果表明,在烧结过程中,金属粘结剂溶解陶瓷相元素并替代陶瓷相的原子。生成相C0.7N0.3Ti和立方Mg0.4Ni0.6O能提高材料的抗弯强度；三方Ti8C5、立方Al3Mg2和立方NiAl2O4能提高材料的硬度；osbornite-TiN、正方Mo2N、立方Al0.96Ni1.94和立方Al09Ni322能提高材料的断裂韧度；镁铝尖晶石、立方MoC、立方NiTi和正交MoNi能提高材料的抗弯强度和硬度,立方AlNi3能提高材料的抗弯强度和硬度,但会降低断裂韧度,正方AlNi3会降低材料的力学性能。研究了陶瓷刀具材料微观组织及其对力学性能的影响。结果表明,金属相对硬质相良好的润湿性、颗粒之间较强的结合力有利于提高陶瓷刀具材料的力学性能。金属相润湿硬质相产生的芯壳结构有利于改善材料的力学性能,尤其能明显提高陶瓷材料的断裂韧度。颗粒尺寸均匀、颗粒间结合力强、添加相对裂纹有钉扎作用的微观组织有利于提高材料的抗弯强度；硬质相颗粒尺寸大、粘结相颗粒尺寸小的微观组织有利于提高材料的硬度；粘结相润湿作用好、颗粒尺寸大、裂纹扩展路径曲折的微观组织有利于提高材料的断裂韧度。研究了TiN含量、烧结温度和保温时间对陶瓷刀具材料力学性能的影响。结果表明,烧结压力为32MPa时, ACU体系陶瓷刀具材料的最佳烧结工艺参数为1650。C和30min,在此工艺下AC2U陶瓷刀具材料的抗弯强度、维氏硬度和断裂韧度分别为853.1MPa、20.23GPa和6.75MPa.m。ACUN体系陶瓷刀具材料的最佳烧结工艺参数为1600℃和50min,在此工艺下AC2U4N陶瓷刀具材料的抗弯强度、维氏硬度和断裂韧度分别为861.1MPa、20.83GPa和6.97MPa·m1/2。AN体系陶瓷刀具材料的最佳烧结工艺参数为1700℃和45min,在此工艺下Al203-10vol%TiNn陶瓷刀具材料的抗弯强度、维氏硬度和断裂韧度分别为896.8MPa、21.08GPa和7.90MPa·m1/2。ANU体系陶瓷刀具材料的最佳烧结工艺参数为1650℃和30min,在此工艺下ANU25陶瓷刀具材料的抗弯强度、维氏硬度和断裂韧度分别为444.2MPa、21.57GPa和8.81MPa·m1/2。通过复现实验成功研制了三种新型氧化铝基陶瓷刀具,即AC2U(Al203-20vol%TiC-10vol%TiNμ)、AC2UN2(Al203-20vol%TiC-3vol%TiNμ-7vol%TiNn)和AC2UN4(Al203-20vol%TiC-2vol%TiNμ-8vol%TiNn)。AC2U的抗弯强度、维氏硬度和断裂韧度分别为876.5MPa、20.96GPa和6.75MPa.mm。AC2UN2的抗弯强度、维氏硬度和断裂韧度分别为887.2MPa、20.21GPa和5.94MPa.m1/2。AC2UN4的抗弯强度、维氏硬度和断裂韧度分别为904.2MPa、19.54GPa和5.85MPa·m1/2。性能良好且较稳定。研究了新型氧化铝基陶瓷刀具连续切削淬硬40Cr合金钢和淬硬T10A碳素工具钢时的切削性能。结果表明,在ap=0.1mm的条件下连续切削淬硬40Cr时,陶瓷刀具AC2U在低速和小进给量条件下的抗磨损能力较好,但切削后期易发生崩刃；陶瓷刀具AC2UN4在高速和大进给量条件下的抗磨损能力较好。在户0.1mm/r和ap=0.1mm的条件下连续切削淬硬T10A时,陶瓷刀具AC2U和AC2UN2的抗磨损性能均优于LT55。更多还原

【Abstract】 In this paper, the novel alumina matrix ceramic cutting tool materials were designed and fabricated. The effects of material components, sintering temperature and sintering time on the phase composition, microstructure and mechanical properties of the alumina matrix ceramic cutting tool materials were analyzed. The cutting performance of the novel alumina matrix ceramic cutting tools was studied.The design scheme for the novel alumina matrix ceramic cutting tool materials was proposed. Micron Al2O3was chosen as the matrix and micron TiC, micron TiN, nanometer TiN were chosen as the additives. MgO was added as the sintering aids, Ni and Mo were added as the metal binders. Four kinds of Al2O3matrix ceramic cutting tools materials were fabricated, which were Al2O3-TiNn ceramic cutting tool materials (AN), Al2O3-TiNn-TiNμ ceramic cutting tool materials (ANU), Al2O3-TiC-TiNμ ceramic cutting tool materials (ACU), and Al2O3-TiC-TiNμ-TiNn ceramic cutting tool materials (ACUN).The phase composition and its effects on the mechanical properties were investigated. The results showed that the metal binders dissolved the elements of the ceramic phases and replaced the atoms of the ceramic phases during the sintering process. The final phases such as C0.7N3.3Ti and cubic-Mg0.4Ni0.6O could improve the flexural strength. The final phases such as trigonal-Ti8C5, cubic-Al3Mg2and cubic-NiAl2O4could improve the hardness. The final phases such as obornite-TiN, tetragonal-Mo2N, cubic-Al0.96Ni1.9494and cubic-Alo.9Ni3.22could improve the fracture toughness. The phases such as spinel-MgAl2O4, cubic-MoC, cubic-NiTi and orthorhombic-MoNi could improve the flexural strength and hardness at the same time, the phase cubic-AlNi3could increase the flexural strength and hardness, but it would decrease the fracture toughness. The phase tetragonal-AlNi3would decrease the mechanical properties. The microstructure of the ceramic tool materials and its effects on the mechanical properties were studied. The results showed that the mechanical properties were better when the microstructure was dense, the metal phases wetted the hard phase well and the adhesive strength among particles was strong. The core-rim structures which were formed by the wetting effect of metal phases on the hard phases could improve the mechanical properties, where the fracture toughness could be improved significantly. The flexural strength could be improved when the particles in the microstructure were uniform, the adhesive strength among particles was strong and the additives had pinning effect on the crack. The Vickers hardness could be improved when the hard phase particles were big while the binding phase particles were small. The fracture toughness could be improved when the metal phases wetted the hard phase well, the particles were big and the crack propagation path was tortuous.The effects of TiN content, sintering temperature and sintering time on the mechanical properties were investigated. The results showed that when the sintering pressure was32MPa, the optimized sintering process for the ACU material system was1650℃and30min, in which AC2U ceramic cutting tool material owned the flexural strength of853.1MPa, Vickers hardness of20.23GPa and fracture toughness of6.75MPa·m1/2. The optimized sintering process for the ACUN material system was1600℃and50min, in which AC2U4N ceramic cutting tool material owned the flexural strength of861.1MPa, Vickers hardness of20.83GPa and fracture toughness of6.97MPa·m1/2. The optimized sintering process for the AN material system was1700℃and45min, in which Al2O3-10vol%TiNn ceramic cutting tool material owned the flexural strength of896.8MPa, Vickers hardness of21.08GPa and fracture toughness of7.90MPa·m1/2. The optimized sintering process for the ANU material system was1650℃and30min, in which ANU25ceramic cutting tool material owned the flexural strength of444.2MPa, Vickers hardness of21.57GPa and fracture toughness of8.81MPa·m1/2.Three kinds of novel Al2O3-TiC-TiN ceramic cutting tools were developed successfully after repeatability tests, which were AC2U micro-composite ceramic cutting tool (Al2O3-20vol%TiC-10vol%TiNμ), AC2UN2nano-composite ceramic cutting tool (Al2O3-20vol%TiC-3vol%TiNμ-7vol%TiNn) and AC2UN4nano-composite ceramic cutting tool (Al2O3-20vol%TiC-2vol%TiNμ-8vol%TiNn). The flexural strength, Vickers hardness and fracture toughness of AC2U were876.5MPa,20.96GPa and 6.75MPa·m1/2, respectively. The flexural strength, Vickers hardness and fracture toughness of AC2UN2were887.2MPa,20.21GPa and5.94MPa·m1/2, respectively. The flexural strength, Vickers hardness and fracture toughness of AC2UN4were904.2MPa,19.54GPa and5.85MPa·m1/2, respectively. The mechanical properties of the novel ceramic cutting tools were good and steady.The cutting performance of the novel alumina matrix ceramic cutting tools was investigated in continuous turning the quenched alloy steel40Cr and quenched carbon tool steel T10A. The results showed that when turning quenched40Cr continuously with the cutting depth ap=0.1mm, AC2U had better wear resistance at a low cutting speed and small feed, but tool breakage was liable to happen at the end of turning process. AC2UN4had better wear resistance at a high cutting speed and big feed. When turning quenched carbon tool steel T10A continuously with the cutting depth ap=0.1mm and the feed f=0.1mm/r, the novel ceramic cutting tools AC2U and AC2UN2both showed better wear resistance than LT55.更多还原