磨料预钎焊金刚石工具的基础研究

发布时间：2018-08-20 18:06

【摘要】：随着科学技术的发展和社会的进步,烧结金属结合剂金刚石工具的应用越来越广泛,但是金属结合剂对金刚石磨料把持强度弱成为影响工具使用寿命的最主要因素。围绕金刚石磨料的把持强度这个关键问题,论文提出了利用高温钎焊技术对金刚石磨料进行表面金属化处理的新工艺,即金刚石磨料预钎焊工艺,利用此工艺制备了预钎焊金刚石磨料及其工具。本文完成的具有创新意义的研究工作主要包括:(1)开发出金刚石磨料预钎焊工艺,采用添加了Cu Ce合金粉的Ni Cr合金复合钎料和Cu Sn Ti合金钎料分别制备了预钎焊金刚石,分析了预钎焊金刚石的抗压强度,两种钎料对金刚石所造成的强度损失分别为12%和4.6%,均满足使用要求。(2)确定了复合钎料中Ni Cr合金含量的最佳范围为30%~35%。利用扫描电镜、能谱仪和X射线衍射仪分析了预钎焊金刚石的结合区域微结构、预钎焊金刚石节块的结合区域以及节块断口。结果表明,添加了Cu Ce合金粉的Ni Cr合金复合钎料与金刚石形成了化学结合,Ni Cr合金预钎焊金刚石节块的界面结合强度高于无预钎焊金刚石节块。(3)确定了Cu Sn Ti合金预钎焊金刚石的平均增重系数不宜超过6.4%。利用扫描电镜、能谱仪和X射线衍射仪分析了预钎焊金刚石的结合区域微结构、预钎焊金刚石节块的结合区域以及节块断口。结果表明,Cu Sn Ti合金钎料与金刚石形成了化学结合,Cu Sn Ti合金预钎焊金刚石节块的界面结合强度高于无预钎焊金刚石节块。(4)利用ANSYS有限元仿真研究了金刚石磨粒的几何形态、磨料浓度、碳化物层厚度以及预钎焊层面积等因素分别对预钎焊金刚石节块的整体应力分布及其力学性能的影响规律,仿真结果的变化趋势与试验结果一致。(5)采用预钎焊金刚石磨粒制备了开槽磨轮,进行了无预钎焊金刚石磨轮、Ni Cr合金复合钎料预钎焊金刚石磨轮和Cu Sn Ti合金预钎焊金刚石磨轮的加工性能试验研究。结果表明:添加了Cu Ce合金粉的Ni Cr合金复合钎料中Ni Cr合金的含量为35%或30%时,磨轮的综合加工性能最好;当Cu Sn Ti合金预钎焊金刚石的平均增重系数为6.4%时,磨轮的锋利度和使用寿命均最高;两种预钎焊金刚石磨轮的加工性能均优于无预钎焊金刚石磨轮。
[Abstract]:With the development of science and technology and the progress of society, the application of sintered metal binder diamond tools is becoming more and more extensive, but the weak holding strength of metal binders to diamond abrasives is the most important factor that affects the service life of tools. Focusing on the key problem of holding strength of diamond abrasives, a new technology of surface metallization of diamond abrasives using high temperature brazing technology, I. E. diamond abrasive prebrazing technology, is put forward in this paper. The prebrazing diamond abrasive and its tools were prepared by this process. The main work of this paper is as follows: (1) the pre-brazing process of diamond abrasive is developed, and the pre-brazing diamond is prepared by using the Ni / Cr alloy composite solder and the Cu / Sn / Ti alloy brazing filler metal, respectively, which have been added with Cu / C _ e alloy powder, and the results are as follows: (1) the diamond pre-brazing technology is developed. The compressive strength of pre-brazed diamond is analyzed. The strength losses caused by the two kinds of brazing filler metals to diamond are 12% and 4.6%, respectively, which meet the requirements of application. (2) the optimum range of Ni / Cr alloy content in the composite brazing alloy is determined to be 30% and 35% respectively. The microstructure of the bonding zone of prebrazed diamond, the bonding area of prebrazed diamond and the fracture surface of pre-brazed diamond were analyzed by means of scanning electron microscope, energy spectrometer and X-ray diffractometer. The results show that The interfacial bonding strength of the chemically bonded Ni / Cr alloy pre-brazed diamond knots is higher than that of the non-brazed diamond knots. (3) the pre-brazing of Cu, Sn and Ti alloys has been determined. The average weight gain coefficient of diamond should not exceed 6.4. The microstructure of the bonding zone of prebrazed diamond, the bonding area of prebrazed diamond and the fracture surface of pre-brazed diamond were analyzed by means of scanning electron microscope, energy spectrometer and X-ray diffractometer. The results show that the interfacial bonding strength of the pre-brazed diamond knots formed between the brazing alloy and the diamond is higher than that of the non-brazed diamond segment. (4) the geometry of diamond abrasive particles is studied by ANSYS finite element simulation. The effects of abrasive concentration, thickness of carbide layer and area of prebrazing layer on the overall stress distribution and mechanical properties of pre-brazed diamond joints are investigated. The variation trend of the simulation results is consistent with the experimental results. (5) the slotted grinding wheel is prepared by pre-brazing diamond abrasive particles. The machining properties of diamond grinding wheel without pre-brazing diamond grinding wheel and pre-brazing diamond grinding wheel with Cu _ (Sn) Ti alloy prebrazed with Ni / Cr alloy composite brazing alloy were studied. The results show that when the content of Ni / Cr alloy is 35% or 30%, the comprehensive processing property of grinding wheel is the best, and the average weight gain coefficient of pre-brazed diamond is 6.4%. The sharpness and service life of the grinding wheel are the highest, and the processing performance of the two pre-brazed diamond grinding wheels is better than that of the non-brazed diamond grinding wheel.
【学位授予单位】：南京航空航天大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TG731

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