铝镁硼钛多元复杂结构新型超硬磨料的制备及磨粒加工性能研究

In this proposal the novel superhard abrasive of “Aluminium-Magnesium-Boron-Titanium” with multi-element and complex crystal structure is put forward and the fabrication mechanism of the abrasive and its machining ability will be investigated. The composition and processing parameters are going to be optimized for preparing Aluminum-Magnesium-Boron-Titanium material. The mechanism of synthesizing Aluminium-Magnesium-Boron-Titanium composite will be investigated. The effect of crystal structure and defects characteristics on the hardness of the materials is to be analyzed, and the geometry of cutting edges and impact resistance of abrasives in different particle size will also be examined. The thermal and chemical stability of the abrasives under the condition of high temperature, different environmental atmosphere, using different coolants, machining iron-based materials will be studied along with the analyzing the chemical reaction and corrosion loss of abrasive. The material removal mechanism and wear mechanism of single abrasive grit are to be obtained for grinding hardened bearing steel and austenitic stainless steel, respectively. The grinding mechanism of abrasive wheel made of Aluminum-Magnesium-Boron-Titanium for grinding hardened bearing steel and austenitic stainless steel is also to be explored. The effect of particle size and concentration of abrasives on grinding force, grinding ratio and grinding temperature will be investigated under different grinding parameters. The protrusion, wear and failure mechanisms of the abrasive wheel in the grinding process will also be investigated.

本项目提出铝镁硼钛多元复杂结构新型超硬磨料的制备及磨粒加工性能的研究，通过多元成分掺杂与复合，优化成分与烧结工艺，探索铝镁硼钛超硬材料的合成机理，掌握铝镁硼钛材料的晶体结构和缺陷特征对硬度影响的微观机制；研究铝镁硼钛材料破碎和粉碎过程的断裂机理，分析不同筛分粒度对磨粒切削刃几何特征以及磨粒抗冲击性能的影响规律；研究磨料的热稳定性和化学稳定性，掌握磨料在高温、环境气氛、冷却液种类以及加工铁基材料时的反应机理和损耗规律。以高硬度淬硬轴承钢和低硬度奥氏体不锈钢为代表，研究单颗铝镁硼钛磨粒在加工两种钢材过程中的材料去除机理及磨粒磨损机理；探索铝镁硼钛磨料制备的磨具加工淬硬轴承钢和奥氏体不锈钢过程中的磨削机理，研究磨粒粒度、浓度在不同磨削工艺参数下对磨削力、磨削比、磨削温度等的影响规律，掌握磨具的出刃、磨损及失效机理。

本课题提出AlMgB14新型超硬磨料的制备研究，在AlMgB14粉体材料、AlMgB14块体材料及其复合材料和AlMgB14磨料等方面开展了一系列的基础研究工作。通过对AlMgB14基础理论和关键制备工艺进行分析及大量的实验研究，获得纯度较高、粒度细小均一和性能稳定的AlMgB14粉体材料。通过研究添加TiB2、Ni3Al、SiCw和Y2O3对AlMgB14超硬材料微观结构和性能的影响，拓宽AlMgB14改性的思路和途径。采用放电等离子烧结（SPS）工艺制备出致密度高达99.25%，显微硬度高达35.5 GPa和断裂韧度高达3.00 MPa·m1/2的AlMgB14块体材料。通过添加TiB2和Y2O3制备AlMgB14-TiB2、AlMgB14-Y2O3和AlMgB14-TiB2-Y2O3复合材料，研究AlMgB14复合材料的微观结构和力学性能，探讨TiB2和Y2O3对AlMgB14材料的增强增韧机理，为后续AlMgB14及其复合材料的开发应用提供理论研究基础。AlMgB14-TiB2复合材料的硬度和断裂韧度随着TiB2含量的升高均呈现出先升高后降低的趋势；添加AlMgB14-30 wt.%TiB2复合材料平均硬度达39.7 GPa，平均断裂韧度达3.53 MPa·m1/2。添加TiB2的增强机制以硬质颗粒弥散强化为主，增韧机制以裂纹偏转增韧为主。AlMgB14-Y2O3复合材料的硬度随着Y2O3含量的增加呈现出先升高后降低的趋势，而断裂韧性则呈现出随Y2O3含量增加而升高的趋势；AlMgB14-3 wt.%Y2O3复合材料的平均硬度高达35.8 GPa，AlMgB14-9 wt.%Y2O3平均断裂韧度达3.14 MPa·m1/2。添加Y2O3后，Y元素在晶界处的分布和沉积，晶界强化增韧效果明显。AlMgB14-TiB2-Y2O3复合材料的致密度、硬度和断裂韧度随着Y2O3含量的升高均呈现出先升高后降低的趋势。添加3 wt.%Y2O3复合材料的平均显微硬度达38.7 GPa，平均断裂韧度达3.71 MPa·m1/2。添加TiB2和Y2O3的增强机制以硬质相颗粒弥散强化为主，增韧机制以裂纹偏转增韧和晶界强化增韧为主。采用AlMgB14粉体材料造粒、AlMgB14块体材料破碎以及激光刻蚀的方法制备AlMgB14超硬磨料，为后续磨具制备及创新思路研究工作的开展打下基础。