影响表面缺陷磁粉探伤检测质量的研究

磁粉检测被认为是表面裂纹检测最灵敏的方法之一,尤其是在表面不平或表面不规则性与所需检测的裂纹相比大得多的情况下,磁粉探伤通常被考虑为表面裂纹检测最好的方法.介绍表面缺陷磁粉探伤原理,对磁粉探伤的磁痕特性,磁痕形成受到磁粉性能、磁化规范、磁悬液的浓度和黏度、零件表面状况、裂纹形状等因素的影响进行分析,为提高磁粉探伤检测质量,操作中需要综合考虑这些因素,以便于使工件的表面缺陷经磁化形成的磁痕能清晰地显示出来而且能被准确地予以判断,提高表面缺陷检测准确性.     

快速凝固TiAl基合金微晶的显微组织

用气体雾化方法制备了Ti-34Al-2Mn合金的微晶粉末,粉末典型粒度为27μm。X射线衍射结果表明,快冷态的粉末主要由α_2相和少量γ相组成。金相组织显示出等轴块状晶粒和树枝状结晶两种形态。经900℃,2h真空退火后,大部分α_2相转变成γ相,使原来的组织更加细化。     

Effect of amide type modified rapeseed oil as lubricating additive on friction and wear behavior of steel-steel and steel-aluminum alloy systems

A new type of environmentally friendly lube additive-amide type modified rapeseed oil was synthesized and characterized by infrared spectrum. Its effect on the friction and wear behavior of steel-steel and steel-aluminum alloy systems were investigated with a four-ball machine and an Optimol SRV friction and wear tester respectively.The morphographies of the worn surfaces were analyzed by means of scanning electron microscopy(SEM). The worn surfaces of the 2024Al alloy block were analyzed by means of X-ray photoelectron spectroscopy(XPS). The results show that the modified rapeseed oil as additives can obviously decrease the wear rate and friction coefficient of steel pair and steel-aluminum frictional pair. Its lubrication mechanism is inferred that a high strength complex protection films form on the worn surface of the Al alloy due to the adsorption or tribochemistry reaction of a long chain additive molecule and high reaction activity of N element.     

Al2O3基多元纳米复相陶瓷的制备及其超塑性

采用溶胶-凝胶法制备了Al2O3-ZrO2（3Y）-Spinel纳米复合粉体，其颗粒大小为20-30nm，粒度分布均匀，无硬团聚。采用真空热压烧结工艺制备了纳米复相陶瓷，结果表明：由于纳米复合粉体中的第二相阻止了基体Al2O3的致密化，纳米复合粉体的烧结温度较普通微米粉体相比并没有大幅度降低，其合适的烧结温度为1450～1500℃。烧结体的超塑性压缩试验表明：在1500℃材料表现出良好的超塑变形能力，变形抗力小于30MPa。在整个压缩变形过程中，材料没有出现明显的应变软化，显示出与超塑性拉伸变形截然不同的特性。     

铑(Ⅲ)氯水配合物的制备及紫外可见光谱的研究

采用封管氯化的方法[1 ] ,制得铑的标准溶液。在一定条件下处理H3[RhCl6]溶液 ,获得K2 [Rh(H2 O)Cl5]、K3[RhCl6]和 [Rh(H2 O) 6]·(ClO4) 3种态。以K2 [Rh(H2 O)Cl5]和K3[RhCl6]为起始物 ,利用国产 71 7阴离子树脂 ,分别得到trans - [Rh(H2 O) 4 Cl2 ]+、cis- [Rh(H2 O) 4 Cl2 ]+、mer- [Rh(H2 O) 3Cl3]、fac- [Rh(H2 O) 3Cl3]和cis- [Rh(H2 O) 4 Cl4]- 种态。研究它们的紫外 -可见吸收光谱发现 ,随着配位内界水分子数的增加 ,其特征吸收峰表现为紫移。通过分析和研究它们的极性及特性吸收峰 ,提出了铑 (Ⅲ )氯水配合物新的鉴别方法。     

基于SLS原型的快速(重力)铸造工艺

结合SLS快速成形和铸造工艺可以实现金属零件的快速铸造.根据原型材料可熔融和烧失的特性,制定了类似于熔模铸造的快速铸造工艺方案.讨论了快速金属铸件的特点,对快速铸造工艺提出了成功率高、成形性好和性能较高的要求.分析了面向金属零件快速铸造的重力铸造工艺并以实例说明,顶注式浇注系统适用于结构简单且高度不大的快速零件,而阶梯式浇注系统适用于中大型和复杂程度较高的铸件.     

快凝钛合金中富Nd弥散相的析出及其长大规律

系统研究了热处理对Ｔｉ－５Ａｌ－１．５Ｎｄ，Ｔｉ－５Ａｌ－４Ｓｎ－１．５Ｎｄ（质量分数，％）两种钛合金中析出相长大规律的影响．结果表明，含Ｎｄ的钛合金的快凝态基体中分布着大量近球状的析出相，并沿晶体的晶界、亚晶界、位错线等处呈串状析出．在６５０－８００℃温度范围内经不同时间热处理后，析出相逐渐聚集长大，但长大速度都很慢．Ｔｉ－５Ａｌ－１．５Ｎｄ合金中析出相为立方的Ｎｄ_２Ｏ_３，其长大激活能为１１７ｋＪ／ｍｏｌ．加入Ｓｎ后，析出相的分布更加弥散，析出相中Ｎｄ和Ｓｎ的平均原子比为１．３７：１，经衍射花样的标定，判定为正交的Ｎｄ_５Ｓｎ_４，其长大速度更慢，长大激活能为１７０ｋＪ／ｍｏｌ．     

一种钛合金冷拉伸用润滑涂层研制

采用化学方法研制出1种新的冷拔用润滑剂涂层，该表面涂层与钛基材结合力强，表面呈灰色，主要成分为Na3TiOF5。该涂层与石墨乳和二硫化钼混合配套使用可大大减小拉伸摩擦阻力，提高钛材表面质量。     

双回转送进二辊冷轧管机凸轮设计研究

本文提出了双回转送进二辊冷轧管机凸轮理论轮廓曲线的新设计方法 ,其轮廓曲线加速度与跃度呈梯形 ,且跃度边界连续 ,给出了针对双回转送进二辊冷轧管机的两个过渡段具有等加速度和跃度的设计准则     

Mechanisms of nanostructure and metastable phase formations in the surface melted layers of a HCPEB-treated D2 steel

This work investigates the mechanism of surface modification associated with the high-current pulsed electron beam (HCPEB) treatment of a D2 steel with increasing numbers of pulses. The surface layers were melted and resolidified but the treated surfaces showed very different features. This variation is essentially due to the different levels of homogeneity and carbide dissolution. It is demonstrated that the presence of carbides served as nucleation sites for the surface eruption phenomenon that creates craters on the surface. After a sufficient number of pulses, most of the carbides in the surface layer were dissolved and an almost crater-free homogeneous melted layer consisting of a very stable nano-austenite structure was formed. The HCPEB technique is thus demonstrated to be a versatile technique for surface microstructure modification involving, in the case of steels, austenite stabilization and ultrafine grain formation.