新型陶瓷刀具的发展与应用

回顾了陶瓷刀具的发展简况及其意义,重点介绍了Si3N4基和TiCN基复合陶瓷刀具的研制、性能和应用.复合Si3N4陶瓷刀具有较高的耐磨性和抗冲击性,特别适合于各类铸铁件的粗精加工,也能进行铣削、刨削等冲击力很大的加工,其切削效率可提高3～10倍;复合TiCN金属陶瓷刀具具有很高的硬度和耐磨性,特别适合于各类高硬高强钢(如淬硬钢等)的加工,可对高硬材料实现"以车代磨"干切削,免除退火工艺和冷却液,大幅度提高生产效率.新型复合陶瓷刀具已经在我国冶金、水泵、矿山机械、轴承、滚珠丝杠、汽车、军工等十几个行业得到应用.     

发动机陶瓷镶块摇臂参数化优化设计系统研究

在反求原锻钢摇臂的基础上进行参数分析,建立了发动机铝合金陶瓷镶块摇臂的参数化设计模型,对此模型施加约束并参数驱动实现新产品的设计,用有限元计算结果对设计结果进行优化.开发了基于Pro/E的CARE/CAD/CAE铝合金陶瓷镶块摇臂参数化优化设计系统,并给出了设计实例.     

Processing and oxidation of co-deposited Ni-Al coatings

Electrodeposited Ni matrix/Al microparticles or nanoparticles dispersed composite coatings (termed as EMCCs or ENCCs) are developed from a Ni-based electrolyte bath. The Al microparticles are in a size range of 1 -5 μm and the Al nanoparticles in an average size of 75 nm. The Al content in coatings increases with increase in the particle content in the bath. Particle size effect on the degree of codeposition is not significant. However, codeposition of Al nanoparticles instead of microparticles promotes more homogenous growth of Ni deposits on {111}, {200} and {220} planes. The oxidation at 1 050 ℃ of the as-deposited composite coatings shows that at a comparable Al content, ENCC of Ni-Al exhibits a better oxidation resistance than EMCC of Ni-Al due to the fast formation of an alumina scale during the transient stage of oxidation.     

Surface finish generated in hard turning of quenched alloy steel parts using conventional and wiper ceramic inserts

Significant progress has already been achieved in green manufacturing including dry and hard, often high-speed, machining technologies. For instance, the demand for higher productivity has resulted in the wider application of ceramic and PCBN tools with special multi-radii (wiper) geometry. This paper reports some important characteristics of the surface roughness produced in the turning of a hardened low-chromium alloy steel using mixed alumina–titanium carbon (TiC) ceramic cutting tools equipped with both conventional and wiper inserts. The characteristic geometrical features of surfaces obtained in both these turning operations have been assessed by means of representative two-dimensional (2D) surface roughness parameters, and some 3D visualizations, which allowed more complete characterization of the surface topography and prediction of its service properties. Results show that keeping equivalent feed rates, i.e. 0.1 mm/rev for conventional and 0.2 mm/rev for wiper tools, the surfaces obtained have similar 3D height roughness parameters, and comparable values of skew and kurtosis. At defined cutting parameters, surfaces produced by wiper tools contain blunt peaks with distinctly smaller slopes resulting in better bearing properties. Only marginal changes of Ra parameter were recorded during 15 min machining trials.     

预氧丝在氧化镁/炭复合材料中的原位碳化及其强化作用

研究了碳纤维前驱体即预氧丝在氧化镁／炭复合材料中原位碳化及其强化作用。在氧化镁／炭复合材料中存在铝、镁添加剂时，预氧丝原位碳化后具有碳纤维的强度和强化效果。预氧丝在添加硅粉的氧化镁／炭材料中原位碳化时因与硅反应失去强度，在无抗氧化添加物的氧化镁／炭材料中原位碳化后，预氧丝因氧化失去强度，对基体无强化作用。     

原位合成ZrC颗粒增强锆基非晶复合材料及力学性能

利用zr与TiC粉末之间的原位反应经铜模铸造方法制备了zrC颗粒增强zr41Til4Cul2.5Ni10Be22．5块状非晶复合材料结果表明：原位合成的ZrC颗粒尺寸细小、形状规整并均匀地分布在非晶基体上．与锆非晶合金相比，复合材料的压缩强度得到提高，塑性得到改善．对ZrC颗粒原位合成及强化机理进行了讨论．     

新型复合材料Mg/MWNTs的储放氢性能

通过在加氢气氛下高能球磨，制成了新型复合材料Mg／MWNTs。利用XRD，TEM—SAED等手段对该材料进行了微结构分析。采用储放氢实验装置测试了Mg／MWNTs—H2体系的PCT放氢曲线和放氢动力学性能。研究发现：复合材料Mg／MWNTs在2．0MPa氢压时，373，473，553和598K温度下，最大储氢量(质量分数)分别为0．41％，3．37％，5．70％和6．25％；复合材料Mg／MWNTs氢化物的焓变和熵变的绝对值均低于纯Mg，分别降低了10．51％和3．50％；与纳米晶Mg氢化物相比，复合材料Mg／MWNTs不仅最大储氢量显著增加，而且放氢动力学性能也明显改善。     

高能球磨制备Al3Ti/Al块体纳米晶复合材料

通过对Al Ti系和Al TiO2 系进行高能球磨和压制烧结制备了固态原位反应生成的纳米晶块体Al3Ti/Al复合材料。研究表明 :Al Ti合金系高能球磨后 ,各组元晶粒得到细化 ,并且Ti在Al中发生了强制超饱和固溶 ,烧结时原位反应形成纳米晶Al3Ti/Al复合材料 ;而Al TiO2 反应体系高能球磨仅发生组分晶粒细化 ,烧结时TiO2 部分还原并和Al原位反应生成纳米晶 (Ti2 O3 Al3Ti) /Al复合材料。     

复合电镀新工艺金刚石钻头的研制与应用

本文采用复合电镀新工艺来研制和生产金刚石钻头。在研制过程中,往普通钻头镀液中加入10g/l金刚石微粉,得到镍—钻—金刚石微粉复合镀层,提高了钻头胎体的耐磨性。将两种品级、三种粒度金刚石按一定比例混合使用,扩大了钻头的适用范围,提高了钻头的自锐性。通过改变内、外径和底唇面镀层厚度的比例,做到镀层基本同步消耗完。一年多来的工地现场使用结果证明,这种钻头适用于坚硬、强研磨性地层的钻进,具有时效快、寿命长的优点。     

Al_2O_3/TiB_2和Al_2O_3/TiB_2/SiC_W陶瓷复合材料在1300℃的氧化行为

研究了热压烧结工艺制备的Al2O3/TiB2和Al2O3/TiB2/SiCW陶瓷复合材料在1300℃的氧化行为用XRD、SEM、TEM/EDSA分析了材料氧化后的相组成及显微结构.结果表明:两种材料在1300℃空气中氧化30h内的氧化增重符合抛物线规律,SiC晶须的加入可明显改善Al2O3/TiB2材料的高温抗氧化性.