Formation of Small Blocky Al3Ti Particles via Direct Reaction Between Solid Ti Powders and Liquid Al

The evolution of titanium powders in the pure aluminum melt at a lower temperature was studied in our research. The process involved some titanium powders being added into the pure aluminum melt at 1003?K (730?°C), and then the melt was cast into an ingot after 5 minutes. A reaction layer composed of some loose Al₃Ti particles was formed on the solid Ti surface due to the reactive diffusion between titanium and aluminum. In-situ blocky Al₃Ti particles smaller than 5???m were produced in the aluminum matrix. A reaction-peeling model was suggested to illustrate the formation mechanism of Al₃Ti particles, and a simple approach for fabricating in-situ Al₃Ti/Al-alloy composites was proposed as well.     

Time-Resolved X-Ray Microtomography Observation of Intermetallic Formation Between Solid Fe and Liquid Al

Time-resolved in situ X-ray tomography combined with scanning electron microscopy was performed on an Al-Fe diffusion system at 973 K (700 °C) to study the formation of the main intermetallic compounds occurring at the interface. After nucleation on the liquid side of the interface, growth occurs in both liquid and solid directions. In the direction of the solid, growth starts with a particular tongue-like feature which then progressively thickens. The thickening is linked to the deformation of the iron matrix during the formation of the intermetallic compound. Growth in the direction of the liquid is slowed down by erosion.     

直接置换法制备包覆型铁铜双金属粉末的工艺研究

以还原铁粉为核心, 以硫酸铜为铜源, 采用直接置换法初步制备包覆型铁铜双金属粉末. 用扫描电子显微镜(SEM)和X射线衍射对粉末的形貌和结构进行了研究, 分析了添加剂、反应时间、干燥还原条件对金属粉末特性的影响, 采用惰气脉冲红外热导法和湿热环境氧化模拟法对粉末的抗氧化性能进行了测试. 试验结果表明: 铁铜双金属粉末为包覆型结构, 添加剂的加入有利于形成致密包覆层, Cu层厚度约为1 μm; 反应时间在25～30 min范围内, 金属收得率最高达到99.5%; 较合适的干燥还原条件应为: 温度在500～650 ℃之间, 时间2～3 h. 在粉末中加入抗氧化剂后, 有效地解决了粉末的氧化问题; 粉末由Cu和Fe两相构成, 没有其他杂质相, 铜的含量为19.53%. 并对大量硫酸亚铁上清液的处理提出了新的方法. 硫酸亚铁上清液可以作为生产金刚石工具用的超细Fe基预合金粉末的原料, 此方法具有简单合理、成本低、环保、产品附加值高的优点.     

The Effect of Solid Particles on Liquid Viscosity

The viscosities of solid‐liquid mixtures were experimentally determined for silicon oil‐paraffin system at room temperature and solid‐liquid oxide mixture at steelmaking temperature. The use of oil‐paraffin systems was to confirm the results of high temperature measurements, the experimental conditions being very difficult to control. The silicon oil‐ paraffin mixtures behaved Newtonian until the particle fraction reached 0.15. At this fraction, the mixture started deviate from Newtonian flow; though some average values could still be collected with very high uncertainty. Liquid‐2CaO.SiO₂ mixtures and liquid‐MgO mixtures were studied at steelmaking temperature with carefully prepared particle fractions and well controlled conditions. Liquid‐2CaO.SiO₂ mixture behaved Newtonian even when the particle fraction reached 0.1. The results of both room temperature measurements and steelmaking temperature measurements were used to examine the applicability of the existing models. Einstein‐Roscoe equation was found to be the only model applicably for the systems studied. No modification of the model parameter was found necessary, though the particles were not spherical.     

全球三大盐酸法钛白制备工艺及进展分析

介绍了全球盐酸法钛白的三大主要制备工艺:美国ANI法、 加拿大CTL法和中国ZLC法.通过对各自工艺特点的对比认为,美国ANI工艺和加拿大的CTL工艺是以钛元素萃取为目标,而中国的ZLC工艺是通过萃取铁元素来达到对钛元素的有效分离.此外,还对上述三大主要盐酸法钛白工艺的优劣势及应用情况进行了分析和阐述,并结合现有研发实...     

用Matano法计算Ti基Al膜的反应扩散系数

本文主要是通过Ti基与Al膜反应动力学提供的浓度分布曲线,用Matano方法计算Ti基Al膜在Ti相变点(880℃)上、下的反应扩散系数,求出扩散激活能,找出了扩散系数与温度和成分的变化规律。     

The Rate of the Phosphorous Reaction Between Liquid Iron and Slag

In the current study, the rates of dephosphorization and rephosphorization of liquid iron with simulated steelmaking slags were investigated at 1873 K (1600° C). The experiments were conducted in an induction furnace with supplemental heating to maintain a consistent temperature within both the metal and slag phases. An integrated form of the rate equation was used to evaluate the results, assuming mass transfer in both the slag and metal was rate controlling. The results of the current and previous studies indicate that the mass transfer parameter, the slag-metal surface area, and the overall mass transfer coefficient (A*k ₀), decreased as the reaction proceeded. It is proposed that initially when the rate and oxygen flux are high, the interfacial energy decreases, and the interfacial fluid velocity increases causing disruption of the slag metal interface. The consequent increases in interfacial area and interfacial fluid flow cause A*k ₀ to be high initially and then decrease as the oxygen flux decreases.     

铌对Ti_3Al价电子结构及其脆性的影响

应用固体与分子经验电子理论计算了Ｔｉ３Ａｌ 及加入铌后各相的价电子结构， 并从均匀变形因子α、解理能Ｇｃ 及位错行为等方面分析了铌对Ｔｉ３Ａｌ 脆性的影响。铌使Ｔｉ３Ａｌ 合金的α及Ｇｃ 提高； 同时铌也减弱了ＴｉＴｉ 共价键， 增加了基面滑移， 从而导致Ｔｉ３Ａｌ 脆性有本质改善。     

铌对Ti3Al价电子结构及其脆性的影响

应用固体与分子经验电子理论计算了Ｔｉ３Ａｌ及加入铌后各相的价电子结构,并从均匀变形因子α,解理能Ｇｃ及位错行为等方面分析了铌对Ｔｉ３Ａｌ脆性的影响,铌使Ｔｉ３Ａｌ合金的α及Ｇｃ提高;同时氟也减弱了Ｔｉ－Ｔｉ共价键,增加了基面滑移,从而导致Ｔｉ３Ａｌ脆性有本质改善。     

金刚石单晶与其表面钛镀膜之间扩散反应的定量相分析

用X射线光电子谱(简称XPS)对金刚石单晶与其表面钛镀膜的扩散反应进行了定量相分析,成功验证了金刚石晶格中的碳原子与钛镀层之间的反应扩散模型。     

超声波振动对Al-8.0%Cu合金抗裂性的影响

以Al-Cu合金为原材料,研究超声波对Al-8.0%Cu合金热裂倾向性的影响。结果表明,金属熔体经过超声波处理后,合金的抗裂力增大,热裂倾向明显降低,断口为沿晶断裂并且存在明显的液膜拉伸痕迹。     

Production of Rounded Reactive Composite Ti/Al Powders for Selective Laser Melting by High-Energy Ball Milling

Metallurgical and Materials Transactions B - The effect of different regimes of high-energy ball milling (HEBM) on the morphology of reactive Ti–Al powders was studied. It is shown that a...     

Correlation Between Plasma Electrolytic Oxidation Coating on Ti6Al4V Alloy and Cathode Current

Metallurgical and Materials Transactions A - Plasma electrolytic oxidation (PEO) is a common surface treatment method to improve the properties of titanium alloys. Here, the structure, composition...     

Al、Ti处理对低合金钢焊接粗晶区组织的影响

研究了Al、Ti处理对低合金钢焊接粗晶区组织的影响.研究发现:用Al处理时,钢中形成的夹杂物为Al的氧化物和细小的TiN.Al的氧化物和TiN不能促进晶内铁素体的形成,焊接粗晶区主要由粗大的晶界铁素体和平行排列的侧板条铁素体组成.用Ti处理时,钢中形成大量的Al、Ti、Mg、Ca复合氧化物夹杂,其颗粒大小为0.5～3.0 μm,同时还有一定量细小的Ti的氮化物.复合Ti的氧化物具有促进晶内针状铁素体形核的能力,焊接粗晶区主要由晶界铁素体、少量的侧板条铁素体和大量的晶内针状铁素体组成.随焊接热循环高温保温时间增长,晶界铁素体粗大,侧板条铁素体数量减少.相变区的冷却速度减慢,晶界铁素体数量增多,针状铁素体的尺寸显著增大.     

Effect of Al2O3 and MgO on Interfacial Tension Between Calcium Silicate‐Based Melts and a Solid Steel Substrate

The effect of Al₂O₃ and MgO on the interfacial tension between the molten CaO–SiO₂‐based slag and solid steel at 1773 K was studied. The interfacial tension of molten slags slightly increased with increasing Al₂O₃, but no significant change of interfacial tension was observed with higher MgO. Fourier transform infrared (FTIR) of as‐quenched slag samples indicated the slag structure to polymerize with Al₂O₃ additions, but depolymerize with MgO additions. Further detailed studies of the slag surface using X‐ray photoelectron spectroscopy (XPS) showed the fraction of free oxygen ions to decrease with higher Al₂O₃ but remained constant at higher MgO. The results suggested that interfacial tension decreases not only with the depolymerization of the melt, but also with an increase in the free oxygen ions at the molten slag/solid steel interface.     

除气剂和超声波对Al-1.65%Si铸锭除气的影响

研究了除气剂和超声波对Al-1．65％Si铸锭除气的影响，如：没有添加除气剂和超声波处理、只添加除气剂不进行超声波处理、即添加除气剂又进行超声波处理的情况。分析了超声波除气效果的原因。研究结果表明，采用超声波振动处理的方法，可显著地降低铸锭内的含气量。     

Preventing Wetting Between Liquid Copper and Solid Steel: A Simple Extraction Technique

Metallurgical and Materials Transactions B - Copper contamination of end-of-life steel scrap is the main barrier to high-quality recycling. Preferential melting of copper from solid steel scrap is...     

A Study on the Interfacial Reaction Between Liquid Iron and MgO-Based Refractories Containing TiO2

Metallurgical and Materials Transactions B - The interfacial reactions between liquid iron and MgO-based refractories were investigated based on the TiO2 concentration values. Substrates comprising...     

Solidification of Calcium Ferrite Melt Using Ultrasonic Vibration: Effect and Mechanism

Metallurgical and Materials Transactions B - Calcium ferrite (CF) is a very important binder phase in iron ore sintering processes. To improve the microstructure of CF, power ultrasound was...