铝合金表面激光合金化Al-Nb金属间化合物涂层

铝铌合金是具有较高强度及硬度的结构材料和涂层材料。采用 2kW连续波Nd YAG激光在AA60 61Al合金表面制备Al Nb金属间化合物激光合金化改性层。采用功率密度 62 .5J·mm- 2 ,交互作用时间 0 .0 65s ,保护气氩气流量为 2 0L·min- 1 的激光辐照处理工艺 ,可获得无孔洞及裂纹、致密的Al Nb金属间化合物改性层。采用光学显微镜、扫描电子显微镜、能谱仪、X射线衍射仪及显微硬度计 ,研究改性层的表面组织形貌 ,成分分布、组织结构及硬度分布。     

等离子喷涂金属间化合物界面的研究

利用了金相显微镜及扫描电镜，对铝合金上等离子喷涂的Ni、Ni/Al、Ni/Cr/Al、NiCrAlCoY-TiAl3和NiCrAlCoY-AlNi涂层的界面进行热震前后表面形貌、热震后铝断口面及热震后热障层断口面SME观测和分析。并对其结合机理做了探讨。     

Behavior and Mechanisms of Deformation in Intermetallic Compound Al_(66) Mn_9Ti_(25) La

Ｂｅｃａｕｓｅｔｈｅｂｉｎａｒｙｉｎｔｅｒｍｅｔａｌｌｉｃｃｏｍ ｐｏｕｎｄＡｌ3ＴｉｈａｓｔｈｅｔｅｔｒａｇｏｎａｌＤＯ2 2 ｓｔｒｕｃｔｕｒｅｗｉｔｈｔｈｅｌｏｗｓｙｍｍｅｔｒｙ ,ｉｔｉｓｅｘｔｒｅｍｅｌｙｂｒｉｔｔｌｅ .ＢｙｒｅｐｌａｃｉｎｇｏｆａｐａｒｔｏｆＡｌｗｉｔｈＭｎ ,ｉｎｔｅｒ ｍｅｔａｌｌｉｃｃｏｍｐｏｕｎｄＡｌ66Ｍｎ9Ｔｉ2 5 ｗｉｔｈｔｈｅｈｉｇｈｅｒｓｙｍｍｅｔｒｙＬ1 2 ｓｔｒｕｃｔｕｒｅｃａｎｂｅｏｂｔａｉｎｅｄ .Ａｓａｒｅｓｕｌｔ,ａｎｉｍｐｒｏｖｅｍｅｎｔｉｎｐｒｏｐｅｒｔ…     

Study on Improving Solidification Structure of Rare Earth Al-Si Alloys with Electropulse Acting on Liquid Alloy

Electropulse modification (EPM) process, a new physical field method for improving the solidification structure of metals was introduced.Different from other research, EPM is only acting pulse current on melt under liquid state.The solidification structure of Al-Si alloys, A1-Cu alloys,cast iron and steel can be modified obviously with this method: the solidification structure of ZL101 alloy presented the Na and Sr modification and the mechanical properties were enhanced; a large number of primary silicon appeared in the microstructure of ZL109 alloy; the equiaxed grain zone was expanded and the grains were fined in Al-5.0wt% Cu alloy; the graphitization took place in solidification process of molten cast iron; the grain sizes of solidification structure of T8 steel were reduced significantly and the shape of steel pearlites also changed; the equiaxed grain zone increased to 88% from original untreated 19%, the equiaxed grains were fined and the intercrystalline crack was avoided in concasting billet by continuously treating liquid electrical sheet steel in tundish.Effects of rare earths on casting Al-Si alloys were also summarized.The method of modifying the solidification structure of rare earth Al-Si alloys with EPM in producing the alloys was proposed.     

快速凝固Cu-30%Fe合金的液相分解行为

液相分解是一些合金在快速凝固时产生的特殊相变行为。研究了不同冷却速度下Cu-30%Fe合金的凝固过程。Cu-30%Fe二元合金铸锭的微观组织是由铜基体和铁枝晶所组成。当过冷度较大时,位于样品自由表面区域比接近冷却铜板区域的冷却速度小,铁枝晶的存在是该区域微观组织的最大特征,它反映了该区域的凝固方式为正常的凝固方式。样品中心层微观组织的最大特征是存在着尺寸较大的铁球形粒子,它反映了在该区域Cu-30%Fe熔体的凝固过程中过冷液相经历了液相分解过程。数量众多的直径约为几微米的铁粒子和铜基体组成了冷却表面的微观组织。这些铁粒子是被细化了的液相分解铁粒子。液相分解会使合金微观组织产生一定程度的粗化,但提高凝固过程的冷却速度可以显著细化液相分解组织。     

Study on Rare Earth-Containing Phases in TiAl Based Alloys Prepared by Non-Equilibrium Solidification Processing

Ｍｕｃｈａｔｔｅｎｔｉｏｎｈａｓｂｅｅｎｐａｉｄｔｏｒａｐｉｄｓｏ ｌｉｄｉｆｉｃａｔｉｏｎ (ＲＳ)ｔｅｃｈｎｉｑｕｅｓｓｉｎｃｅＤｕｗｅｚｉｎ ｖｅｎｔｅｄ“ｇｕｎ”ｍｅｌｔｉｎｇｔｅｃｈｎｉｑｕｅｗｈｉｃｈｏｂ ｔａｉｎｅｄｃｏｏｌｉｎｇｒａｔｅｓａｓｈｉｇｈａｓ 1 0 7Ｋ·ｓ-1ｉｎ1 96 0ｓ[1] .Ａｓｐｏｔｅｎｔｉａｌｓｔｒｕｃｔｕｒｅｍａｔｅｒｉａｌｕｓｅｄａｔｅｌｅｖａｔｅｄｔｅｍｐｅｒａｔｕｒｅｓ ,ＴｉＡｌｂａｓｅｄａｌｌｏｙｓｈａｖｅｂｅｅｎｌａｉｄｍｕｃｈｅｍｐｈａｓｉｓｉｎｔｈｅｌａｓ…     

粉末冶金快速凝固技术与材料

以粉末冶金快速凝固技术和材料为线索，评述了快速凝固制粉技术的发展，材料特性以及在金属材料领域的应用，最终阐述了该领域的研究现状与发展前景。     

稀土导电铝合金的铸态组织和相组成

本文利用光学显微镜、扫描电镜、Ｘ射线衍射仪等，研究了Ｌａ、Ｃｅ对工业纯铝铸态组织和相组成的影响。结果表明，Ｌａ、Ｃｅ能细化工业纯铝的铸态组织，并和Ｆｅ、Ｓｉ等元素结合生成了二元或三元稀土化合物相。     

Solidification Behavior of Laser Melting Layer of Nd15Fe77B8 Sintered Magnets and Its Microstructures Evolution

To research the solidification behavior and microstructures of a laser remelting/solidification layer on anisotropic Nd15Fe77B8 sintered magnets with their magnetization direction parallel to X, Y, Z-axis respectively, their surfaces (parallel to XOY plane) were scanned by 5 kW Roffin-Sinar 850 type of CO2 laser along Y axis. The rapid solidification of the molten alloy in the layer results in three distinct zones. The transition zone close to the unmolten portion of a magnet (substrate), consists of the columnar Nd2Fe14B phase (matrix), the 10.0%～15.1% dendrite primary iron phase dispersing in the matrix, and the Nd-rich phase along Nd2Fe14B grain boundaries. The columnar crystal zone in the middle of the layer consists of the long columnar Nd2Fe14B grains and their grain boundary Nd-rich phase. And the dendrite crystal zone near the free surface of the layer consists of dendrite Nd2Fe14B grains and their grain boundary Nd-rich phase. When the laser scanning velocity is lower, the growing direction of the microstructures in the layer tends to the laser scanning direction step by step. When the velocity is not lower than 25 mm · s-1, the laser remelting/solidification layer thins and the columnar crystal zone comprises almost the whole layer. Under this condition, on the substrate with its magnetization direction along X or Y-axis respectively, the columnar Nd2Fe14B grains in the layer grow in the direction of Z-axis (that is their long-axis along Z-axis), their alignment of the easy magnetization axis [001] is parallel to the magnetization direction of the substrate correspondingly; but on the substrate with its magnetization direction along Z-axis, the columnar Nd2Fe14B grains in the transition zone grow at an angle of 30°～50° between Z-axis and their long-axis. And the columnar Nd2Fe14B grains in the columnar crystal zone gradually tend to the Z-axis,and their easy magnetization axis [001] arrange in the range of 0°～360° of the plane perpendicular to their long-axis.     

Study on Y-Base Rare Earth Alloy in Ultra-High Hardfacing

The effect of Y-base rare earth alloy in ultra-high hardfacing was observed by means of OM, SEM and XRD. Precipitated carbide can be metamorphosed and spheroidized in surfacing by adding Y-base rare earth alloy, which contributes to the increase of precipitated carbide. Rare earth combined with oxygen and sulfur can improve the morphology of slag inclusion as well as purify surfacing. The result shows proper rare earth alloy in surfacing can fine its microstmcture, improve hardness and impact toughness.     

快速凝固AlSi17Fe6Cu4.5Mg0.5合金的组织及性能

采用超音速气体雾化法制备快速凝固高硅铝合金粉末，通过热挤压法对雾化合金粉末进行固结成形，并利用T6处理工艺对挤压态合金进行热处理。对不同状态合金材料的组织及变化特征进行研究，同时对挤压态及T6处理态合金拉伸性能和耐磨性进行测试。     

单相组织金属间化合物的超塑性行为

在一定条件下具有单相微观组织的L12型[Ni3Al,Ni3(Si,Ti),Co3Ti],L10型（TiAl)和B2型（FeAl,Fe3Al,NiAl)金属间化合物均表现出超塑性行为。其中,L12型和L10型金属间化合物的超塑性变形机制为晶界的滑移,而B2型金属间化合物的超塑性变形则来自于变形过程中发生的动态回复及再结晶,超塑性变形机制的多样性是由于金属间化合物在微观组织及位错结构上（如反向畴界能,层错能和化学成分差异,超位错及界面位错等）比普通金属合金要复杂得多。     

Friction and Wear Characteristics of Mg-Al Alloy Containing Rare Earths

The influence of rare earth on the friction and wear characteristics of magnesium alloy AZ91 and AM60 were studied. The results show that the wear resistance properties of rare earth magnesium alloys are better than those of matrix alloy under the testing conditions. The anti-wear behaviour of AZ91 alloy is much better than that of AM60 alloy. In dry sliding pmcess, magnesium alloys undergo a transition from mild wear to severe wear. The addition of rare earths refine the structure of alloys, improve the comprehensive behaviors of magnesium alloys,increase the stability of oxidation films on worn surfaces,enhance the loading ability of rare earth magnesium alloys,and delay the transition from mild wear to sevre wear effectively.     

Influence of Rare Earths on the Directional Solidification Microstructure of Tin-Lead Eutectic Alloy

ＩｎｆｌｕｅｎｃｅｏｆＲａｒｅＥａｒｔｈｓｏｎｔｈｅＤｉｒｅｃｔｉｏｎａｌＳｏｌｉｄｉｆｉｃａｔｉｏｎＭｉｃｒｏｓｔｒｕｃｔｕｒｅｏｆＴｉｎＬｅａｄＥｕｔｅｃｔｉｃＡｌｏｙＺｈｕＹｉｎｇ（朱颖），ＦａｎｇＨｏｎｇｙｕａｎ（方洪渊），ＱｉａｎＹｉｙｕ...     

快速凝固过程分析

从快速凝固的基本原理着手,详细总结了快速凝固技术的冷却方式判定方法,从物质的导热原理出发讨论了单辊熔体急冷法、双辊熔体急冷法的冷却方式,分别概括了它们的界面导热系数的计算,分析了冷却速度的计算方法。对快速凝固的过程分析具有参考价值。     

Preparation and Corrosion Resistance of Rare Earth Conversion Coatings on AZ91 Magnesium Alloy

Magnesiumalloysarewidelyusedinweaponin dustry,spacenavigationandhavegoodpotentialof applicationanddevelopmentindailycommunication facilitiesduetotheirpropertiesoflightweightandhighstrength[1].Appliedasstructuralmaterials,mag nesiumalloysmayeasilycrackduet…     

马氏体时效钢激冷粉末的时效性

利用SEM技术,观察马氏体时效钢冷冷粉末经480℃、3h时效后的表面,发现有大量的白点相,主要分布于结晶组织的晶臂间,经能谱和波谱分析,鉴别其为Ti的化合物。显微硬度的分析表明,激冷粉末的时效硬度远远高于固溶淬火后的时效硬度,并有可能利用激冷组织的特征来提高马氏体时效钢的性能,并调整其成分。     

5XXX系和7XXX系铝合金中粗大金属间化合物的研究

通过试验研究了5XXX系和7XXX系合金中粗大金属间化合物的形成原因、金属间化合物对材料的影响及消除措施。     

Modification Effect of P ＋ Sr ＋ Ce Compound on Microstructure and Properties of Cast High Silicon Heat-Resist Aluminum Alloy

Modification Effect of P Sr Ce Compound on Microstructure and Properties of Cast High Silicon Heat-Resist Aluminum Alloy     

Study on Ignition Proof AZ91D Magnesium Alloy Chips with Cerium Addition

The effect of Ce on ignition point of AZ91D magnesium alloy chips was studied. For the AZ91D and the AZ91D-xCe magnesium alloys, changing the sizes of the chips in the range of 58 - 270 μm has a limited influence on ignition point, however, the shift of the content of Ce has much effect on ignition point. Increasing the Ce content, x from 0.15 to 0.25, the ignition point increases with increasing of Ce; however, x from 0.25 to 0.45, the ignition point decreases with increasing of Ce. By the addition of Ce of 0.25 %. the ignition point is raised by 43℃.