原位生长TiB_2棒晶增韧陶瓷刀具及其磨损可靠性评价研究

发布时间：2018-01-12 17:15

本文关键词：原位生长TiB_2棒晶增韧陶瓷刀具及其磨损可靠性评价研究　出处：《山东大学》2015年博士论文　论文类型：学位论文

【摘要】：针对目前TiB2基陶瓷刀具的断裂韧度低、高温力学性能研究少、传统制备工艺不完善等问题,本研究提出了原位生长TiB2棒晶增韧TiB2基陶瓷刀具材料反应热压烧结制备工艺技术,研制成功了具有良好室温和高温力学性能及切削性能的新型陶瓷刀具。对陶瓷刀具材料的物相组成、微观组织演变、室温力学性能、高温抗弯强度、棒晶生长机理与生长动力学规律、增韧补强机理、刀具切削性能与可靠性评价等进行了系统深入的研究。反应热压烧结工艺技术的提出和新型陶瓷刀具材料的研制丰富了陶瓷刀具材料的制备工艺,为高性能陶瓷刀具的设计制造理论、研发和应用研究奠定了重要基础。提出了原位生长TiB2棒晶增韧陶瓷刀具材料反应热压烧结制备工艺技术,实现了TiB2棒晶原位生长与陶瓷刀具烧结的一体化制造技术。研制成功了TS系列(TiB2-SiC)陶瓷刀具材料。其断裂韧度随SiC含量的增加而提高,但抗弯强度和硬度均降低。其中TS10 (TiB2-10wt.%SiC)的室温力学性能最优,即抗弯强度为705MPa、断裂韧度为6.6MPa·m1/2、维氏硬度为22.5GPa和相对密度为98.7%。原位生长的TiB2棒晶为单晶,其直径为1-2μm,长径比为3-6,产量为12vol.%。TiB2棒晶的主要增韧补强机理是裂纹偏转、棒晶桥联、裂纹分叉和棒晶断裂。研制成功了TSN系列(TiB2-SiC-Ni)陶瓷刀具材料。Ni的含量显著影响陶瓷刀具材料的室温力学性能。其中TSN5 (TiB2-SiC-5wt.%Ni)的室温力学性能最优,即抗弯强度为1121MPa、断裂韧度为7.9MPa-m1/2、维氏硬度为21.3GPa和相对密度为98.6%。原位生长的TiB2棒晶为单晶,其直径为0.2～1.51μm,长径比为3-10,产量为18vol.%。TiB2棒晶的主要增韧补强机理是裂纹偏转、裂纹分叉、棒晶桥联和棒晶断裂。金属Ni的延性相增韧作用提高了陶瓷刀具材料的断裂韧度。研制成功了TTS系列(TiB2-TiC-SiC)陶瓷刀具材料。原位生成的TiC有效抑制了TiB2晶粒的长大,材料具有均匀细小的微观组织。TiC可诱导TiB2晶粒异向生长成为棒晶,当TiC含量降低时,材料中的TiB2棒晶产量降低。其中TTS(TiB2-TiC-SiC)的室温力学性能最优,即抗弯强度为768MPa、断裂韧度为7.3MPa·m1/2、维氏硬度为21.8GPa和相对密度为99.1%。原位生长的TiB2棒晶为单晶,其直径为0.5-1μm,长径比为3-8,产量为20vol.%。TiB2棒晶的主要增韧补强机理是裂纹偏转、裂纹桥联、裂纹分叉、棒晶断裂和棒晶拔出。研究了原位生长TiB2棒晶增韧陶瓷刀具材料的高温抗弯强度,揭示了陶瓷刀具的高温抗弯强度随温度变化的规律,提出了陶瓷刀具高温抗弯强度的增强与弱化机理。TS系列刀具的抗弯强度随温度的升高而逐渐降低,TS10具有最优的室温及高温抗弯强度；TSN系列刀具的抗弯强度随温度的升高而急剧降低,在800℃以上表现出塑性断裂行为；TTS刀具的抗弯强度随温度的升高先增大尔后降低。新型陶瓷刀具高温抗弯强度的主要增强机理是微裂纹愈合和残余拉应力降低,主要弱化机理是晶界软化、刀具氧化和弹性模量降低。原位生成的SiC提高了TiB2陶瓷的抗氧化性能；原位生成的TiC细化了晶粒,提高了材料的室温和高温抗弯强度；金属Ni提高了材料的室温力学性能,但是同时降低了材料的高温抗弯强度。原位生长TiB2棒晶有效抑制了高温下晶粒滑移和晶粒转动,提高了陶瓷刀具材料的高温抗弯强度。建立了原位生长TiB2棒晶增韧补强陶瓷刀具微观组织演变的几何模型,构建了基于扩散控制的原位生长TiB2棒晶固-液-固(SLS)生长机理模型,创建了原位生长TiB2棒晶桥联和棒晶拔出的增韧补强机理模型。材料的微观组织演变分为原材料混合、瞬时液相、过渡塑性相、晶粒重排和棒晶生长等阶段。原位生长TiB2棒晶的生长受扩散控制,高温下熔融Ti为其生长提供了良好的液相环境。建立了原位生长TiB2棒晶生长动力学模型。在一定温度下,棒晶长度、直径和长径比随着生长时间的延长而增大；在一定生长时间内,棒晶长径比随着温度的升高而增大。研究了新型陶瓷刀具材料的增韧补强机理。建立了原位生长TiB2棒晶桥联和拔出的增韧补强机理模型。研究了棒晶内第二相颗粒、晶内型棒晶、晶内型纳米晶粒、晶间型微／纳米晶粒、位错、延性相和界面结合状态等的增韧补强机理。研究了新型陶瓷刀具加工难加工材料时的切削性能,建立了评价新型陶瓷刀具磨损可靠性的刀具磨损寿命分布模型。研究了新型陶瓷刀具湿式连续切削Invar36合金时的切削性能,TS10的最优切削用量为v=140m/min、f=0.1mm/r和ap=0.4mm,刀具磨损寿命为26.2min；刀具的主要磨损机理是粘结磨损、扩散磨损、氧化磨损和磨粒磨损；建立了评价刀具磨损可靠性的刀具磨损寿命对数正态分布函数和可靠度函数模型；刀具磨损寿命变异系数为0.085,刀具磨损可靠性较高。研究了新型陶瓷刀具湿式连续切削奥氏体不锈钢1Cr18Ni9Ti时的切削性能,TSN5的最优切削用量为v=100m/min、f=0.1mm/r和ap=0.35mm,刀具磨损寿命为24.4min;刀具的主要磨损机理是粘结磨损、扩散磨损和轻微的氧化磨损；建立了评价刀具磨损可靠性的刀具磨损寿命威布尔分布函数和可靠度函数模型,该分布的模数为1.633,刀具磨损可靠性较低。研究了新型陶瓷刀具湿式连续切削热作模具钢H13时的切削性能,ITS的最优切削用量为v=100m/min、f=0.1mm/r和ap=0.25mm,刀具磨损寿命为45.4min；刀具的主要磨损机理是粘结磨损、氧化磨损和磨粒磨损；建立了评价刀具磨损可靠性的刀具磨损寿命对数正态分布函数和可靠度函数模型,刀具磨损寿命变异系数为0.069,刀具磨损可靠性较高。
[Abstract]:Aiming at the fracture toughness of TiB2 ceramic tool is low, high temperature mechanical properties of less, technology is not perfect by traditional system, this study proposes the in situ growth of TiB2 rod crystal toughened TiB2 matrix ceramic tool material prepared by reactive hot pressing sintering technology, the development of new ceramic tool has good room temperature and high temperature mechanical properties and cutting performance the success on the phase composition of ceramic tool materials, microstructure evolution, mechanical properties, high bending strength, good mechanism and regularity of the growth kinetics of crystal growth, the strengthening and toughening mechanism, make a systematic study of cutting performance and reliability evaluation. Put forward and developed a new ceramic tool material reaction process technology of hot pressing sintering enriches the preparation technology of ceramic tool materials, manufacturing theory for the design of high performance ceramic tools, the development and application of research laid an important foundation. The in situ growth of TiB2 rod crystal toughened ceramic material prepared by reactive hot pressing sintering technology, manufacturing technology to achieve the integration of the TiB2 rods in situ growth and sintering of ceramic tool. The successful development of the TS series (TiB2-SiC) ceramic tool material. The fracture toughness increased with the increasing content of SiC, but the flexural strength and hardness decreased. The TS10 (TiB2-10wt.%SiC) the optimal mechanical properties at room temperature, the bending strength is 705MPa, the fracture toughness of 6.6MPa m1/2, Vivtorinox 22.5GPa and hardness of the relative density of 98.7%. in situ growth of TiB2 rod crystal crystal, its diameter is 1-2 m, the ratio of length to diameter is 3-6, the output is the main toughening 12vol.%.TiB2 the crystal rod reinforcing mechanism is crack deflection, crack branching and bridging rod, rod crystal fracture. The development of TSN series success (TiB2-SiC-Ni) content of the ceramic tool material.Ni significantly affect the mechanical ceramic tool materials The performance of the TSN5 (TiB2-SiC-5wt.%Ni). The optimal mechanical properties at room temperature, the bending strength is 1121MPa, the fracture toughness 7.9MPa-m1/2, Vivtorinox hardness is 21.3GPa and the relative density was 98.6%. in situ growth of TiB2 rod crystal crystal, its diameter is 0.2 ~ 1.51 m, the ratio of length to diameter is 3-10, the yield is the main toughening of 18vol.%.TiB2 rod the crystal reinforcing mechanism is crack deflection, crack bifurcation, rod bridging and rod fracture. The ductility of the metal Ni phase toughening effect to improve the fracture toughness of ceramic tool materials. The successful development of the TTS series (TiB2-TiC-SiC) ceramic tool materials. The in situ formed TiC effectively inhibited the growth of TiB2 grains with uniform and fine materials the microstructure of.TiC TiB2 can induce the abnormal grain growth become great crystal, when the TiC content is reduced, reducing the TiB2 rods in the material. The yield of TTS (TiB2-TiC-SiC) of the most excellent mechanical properties at room temperature, the bending strength For 768MPa, the fracture toughness is 7.3MPa - m1/2, Vivtorinox hardness is 21.8GPa and the relative density was 99.1%. in situ growth of TiB2 rod crystal crystal, its diameter is 0.5-1 m, the ratio of length to diameter is 3-8, the yield of the 20vol.%.TiB2 rod as the main toughening and reinforcing mechanism is crack deflection, crack bridging, crack branching, rod crystal fracture and pull rod crystal. The bending strength of high temperature in situ growth of TiB2 rod crystal toughened ceramic material, reveals the high temperature ceramic tool of flexural strength varies with temperature, the bending strength of reinforced flexural strength of high temperature ceramic tool and Weakening Mechanism of.TS series tool with temperature increasing. Gradually reduce the flexural strength at room temperature and high temperature, TS10 has the best; the flexural strength of TSN series tool with the increase of temperature decreased sharply, showing plastic fracture behavior at 800 DEG C; the flexural strength of TTS tool with temperature rise The high first increased and then reduced. The main strengthening mechanism of ceramic cutting tools for high temperature strength of the micro crack healing and reduce the residual tensile stress, the main mechanism of grain boundary weakening is softening, reduce tool oxidation and elastic modulus. The in situ formed SiC improves the oxidation resistance of TiB2 ceramics; TiC in situ grain refinement, improved the bending strength of the material at room temperature and high temperature; metal Ni improves the mechanical properties at room temperature of the material, but also reduces the material of the high temperature bending strength. In situ growth of TiB2 rod crystal can effectively restrain the grain and grain rotation slip under high temperature, bending strength has improved high temperature ceramic tool materials. A geometric model for the evolution of in situ growth the TiB2 rod reinforced ceramic tool microstructure, constructed in situ diffusion control based on the growth of TiB2 rod crystal solid liquid solid (SLS) growth mechanism model, created in situ growth of Ti The B2 rod and bridging rod crystal pull-out toughening mechanism model. The microstructure evolution of materials into raw materials mixing, transient liquid phase, transient plastic phase, grain rearrangement and rod crystal growth stage. The growth of the TiB2 rod in situ was controlled by diffusion, high temperature melt Ti provides good the liquid environment for its students. Established in situ growth of TiB2 rod crystal growth kinetics model. Under certain temperature, rod length, diameter and length to diameter ratio increases with the growth of time; in a certain growth period, rod length diameter ratio increases with the temperature of toughening ceramic. The tool material reinforcing mechanism. Established in situ growth of TiB2 rod crystal bridging and pull-out toughening mechanism model. The study of second phase particles in the crystal rod, intragranular rod crystal, intragranular nano grains, intergranular micro / nano grain, dislocation, ductile phase and interface. The state of the toughening and reinforcing mechanism. On the new ceramic tool cutting performance of hard materials, a tool wear life distribution model evaluation model of ceramic tool wear reliability. On the cutting performance of ceramic cutting tools wet continuous cutting of Invar36 alloy, the optimal cutting parameters of TS10 for v=140m/min, f=0.1mm/r and ap=0.4mm life is 26.2min, the tool wear; the wear mechanism is mainly adhesion wear, diffusion wear, oxidation wear and abrasive wear; a tool wear life reliability assessment of tool wear on the number of normal distribution function and reliability function model; tool wear life of the coefficient of variation was 0.085, tool wear and high reliability. A new study the cutting performance of ceramic cutting tool wet continuous cutting austenitic stainless steel 1Cr18Ni9Ti, the optimal cutting parameters TSN5 v=100m/min, f= 0.1M M/r and ap=0.35mm, the tool wear life of 24.4min; the main wear mechanism is adhesive wear, diffusion wear and slight oxidative wear; establish the evaluation tool wear reliability of tool wear function and reliability function model of life Wipur distribution, the distribution of mode number is 1.633, the tool wear low reliability. On the new ceramic wet continuous cutting heat cutting performance of tool die steel H13, the optimal cutting dosage of ITS is v=100m/min, f=0.1mm/r and ap=0.25mm, the tool wear life of 45.4min; the main wear mechanism is adhesive wear, oxidation wear and abrasive wear; establish the evaluation reliability of tool wear tool wear life of the lognormal distribution function and the reliability function model, tool wear life of the coefficient of variation was 0.069, tool wear and high reliability.

【学位授予单位】：山东大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TG711

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