等离子弧异质异构增材制造构件的组织与力学性能分析

采用等离子弧增材系统实现了不锈钢/高强钢异质异构增材构件制备，等离子弧增材构件具有良好的沉积形貌及优异的力学性能.为揭示叠合方式对等离子弧异质增材构件的宏微观组织和力学性能特征影响，研究采用了体视显微镜、金相显微镜、拉伸及硬度等测试方法.结果表明，不锈钢/高强钢异质异构增材构件中存在两种过渡形式，即以奥氏体枝晶过渡和马氏体组织过渡.增材构件横截面硬度波动较大，主要是混合过渡区域的高合金元素导致的组织变化引起的.叠合方式的改变能够显著影响材料性能，在强度下降不多的情况下，提高材料的冲击韧性.     

Progress in pressureless sintering of boron carbide ceramics – a review

ABSTRACT

Boron carbide (B₄C) ceramics has many outstanding performance, such as extremely high hardness, low density, high melting point, high elastic modulus, high thermoelectromotive force, high chemical resistance, high neutron absorption cross section, high impact and excellent wear resistance. Therefore, B₄C ceramics can be used in various industrial applications, such as lightweight ceramic armour, high temperature thermocouples, neutron absorber, reactor control rods in nuclear power engineering, polishing media for hard materials, abrasive media for lapping and grinding, and wear resistant components (blasting nozzles, die tips and grinding wheels). Pressureless sintering is the method with industrialised application value for B₄C ceramics, however, it is impossible to sinter pure B₄C ceramics to high densities without additives by pressureless sintering. So sintering additives must be used to promote the densification of B₄C ceramics. The different sintering additives used to promote the densification of boron carbide will be described in this review, including carbon additives, metallic additives, oxide additives, non-oxide additives, combined additives and rare earth oxide additives. Finally, the recent research trends for sintering methods and sintering additives of B₄C ceramics will also be proposed.     

基于语言信息一致性调整算法的数据产品选择

针对语言评价信息环境下的数据产品选择问题，设计了一种基于语言偏好关系加性一致性改进算法的数据产品选择模型。以专家提供的语言偏好关系信息为基础，引入了衡量语言偏好关系一致性水平的计算方法，提出了完全加性一致语言偏好关系的构造模型。构建了一种具有收敛性的基于语言偏好关系一致性改进算法的数据产品选择模型。通过数据产品选择实例，发现构建的决策算法更为可靠有效。     

添加剂对航空润滑油橡胶相容性的影响

采用满足MIL-PRF-23699F规范中航空发动机润滑油要求的季戊四醇酯为基础油，研究了3种抗氧剂和3种极压抗磨剂对航空润滑油橡胶相容性的影响。结果表明：磷酸酯极压抗磨剂使丁腈橡胶的体积变化率增大，其他添加剂对丁腈橡胶的体积变化率无显著影响；极压抗磨剂对氟橡胶的体积变化率几乎没有影响，而抗氧剂使氟橡胶的体积变化率有微弱的减小；胺类添加剂在酯类润滑油中对氟橡胶拉伸性能无显著影响；酸性磷酸胺极压抗磨剂使硅橡胶体积发生收缩，使氟硅橡胶的体积变化率减小；酸性磷酸胺极压抗磨剂与硅橡胶和氟硅橡胶可发生化学反应，使橡胶的拉伸性能大幅下降。     

Processing of AlSi9Cu3 alloy by selective laser melting

ABSTRACT

Additive manufacturing of Al-alloys allows the production of components with a complicated structured shape, geometry composed by lattice structures, internal cooling, etc. The portfolio of Al-alloys for metal additive manufacturing is still under development and is strongly limited, compared to the conventional technology. The alloy AlSi9Cu3 is used in many applications, but its processing details are still missing. The main aim of this paper is to describe the laser process parameters for AlSi9Cu3, processed by SLM technology and manufactured from two powders of different shapes and particle sizes. The tested process parameters were laser power, laser speed, and hatch distance in the range of 100–400?W, 200–1500?mm?·?s^?1 and 90–150?µm. These were tested using a single-track and cube test. Microstructure, mechanical properties and the fatigue of SLM samples were analysed and compared with as-casted material.     

绿色环保型的铝材轧制润滑添加剂的研制及其性能

在深入剖析铝材轧制工艺润滑特性的基础上，采用可生物降解的材料，通过对其多种复配机理的研究，研制了一种绿色环保型的CSAQ铝材轧制润滑添加剂。通过四球试验机、TG和DTA热分析、兼容性试验及其它理化分析方法对CSAQ添加剂进行了性能测试，结果表明：CSAQ添加剂具有优良的润滑性、良好的热稳定性和退火清洁性，且与多种基础油和添加剂兼容。急性毒理试验表明：CSAQ添加剂测不出LD50，小鼠每日最大耐受量为80mL／kg。因此，其毒性极其轻微，对人体和环境无毒害作用，符合德国WGK的标准，为绿色润滑添加剂。在工业实际应用中效果良好，可满足现代高速铝材轧机对润滑添加剂的性能要求。     

The effect of atmosphere on the composition of wire arc additive manufactured metal components

ABSTRACT

The effects of atmospheric contamination on wire arc additively manufactured (WAAM) components were studied by producing AM multilayer parts under controlled conditions. Gas impurity levels were maintained using an argon purge box at levels from atmospheric (210,000?ppm O₂) to 1?ppm O₂, and with corresponding levels of nitrogen. Stainless steel (308L), titanium (Ti–6Al–4V) and pure Ta were studied, each having different affinities for oxygen and nitrogen. Results show that WAAM parts made in air produce unacceptable oxygen and/or nitrogen levels for most applications. However, with moderate purging, all three metals can be deposited by WAAM with compositions similar to the starting wire, and the results are used to provide recommended minimum purge box atmospheres for each metal.     

金属对植物油氧化性能影响的微氧化分析

利用微氧化装置考察了N-苯基-2-萘胺在菜籽油中的抗氧化性能以及不同金属对植物油及添加剂氧化聚合速率的影响。结果表明，铜对菜籽油的氧化聚合具有较强的催化作用，并且铜可引发N-苯基-2-萘胺的聚合反应，从而减弱了其抗氧化作用。     

润滑添加剂的结构与性能

本文油性剂，极压剂和摩擦调整剂等润滑添加剂的结构与性能的关系，以及它们在边界润滑和混合润滑状态下的摩擦化学反应特性，研究了各添加剂之间的配伍效果，交列举了一些应用实例。