氧化SiCp增强ZL101铝基复合材料的显微结构

利用光学和电子显微镜研究了液态金属搅拌法处理后金属型铸造和连续铸造ＳｉＣｐ／ＺＬ１０１ 铝基复合材料的显微组织与界面结构特征．结果表明,ＳｉＣｐ 高温氧化后表面生成的ＳｉＯ２ 晶体在复合材料复合与铸造期间与铝合金熔液中的Ｍｇ 、Ａｌ 元素发生界面反应,生成ＭｇＡｌ２ Ｏ４ 和Ｓｉ,促使ＳｉＣｐ 与铝合金润湿,并提高ＳｉＣｐ 的分散性．与普通金属型铸造相比,连续铸造ＳｉＣｐ／ＺＬ１０１ 复合材料的晶粒细小,ＳｉＣｐ 分布十分均匀,ＳｉＣｐ／Ａｌ 界面反应层较薄．     

Thermodynamic Analysis of the Formation of In-situ Reinforced Phases In Cast AI-4.5Cu Alloy

The thermodynamic analysis of the formation of in-situ reinforced phases in (TiB2 Al3Ti)/Al-4.5Cu composites prepared by mixed salts reaction was conducted, and heat changes of mixed salts system were analyzed by differential thermal analysis (DTA). The results show that although TiB2 possesses the strongest formation ability in Al-Ti-B ternary system, [Ti] is relatively excessive in the in-situ reaction and it combines with Al to form Al3Ti phase. The reinforced phases are TiB2 and Al3Ti in the produced composites due to the reaction taking place to form reinforced phase with the addition of mixed salts into Al-4.5Cu melt between 900℃ and 1032℃.     

Reactive Processing and Mechanical Properties of Al/SiCP Composite

0　ＩｎｔｒｏｄｕｃｔｉｏｎＡｌ/ＳｉＣＰｃｏｍｐｏｓｉｔｅｓｈａｖｅｈｉｇｈｓｐｅｃｉｆｉｃｓｔｒｅｎｇｔｈａｎｄｍｏｄｕｌｕｓ,ｈｉｇｈｗｅａｒｒｅｓｉｓｔａｎｃｅａｎｄｇｏｏｄｗｏｒｋａｂｉｌｉｔｙ .Ｔｈｅｙｓｈｏｗｇｏｏｄｐｒｏｓｐｅｃｔｆｏｒｉｎｄｕｓｔｒｙａｐｐｌｉｃａｔｉｏｎ .Ｔｈｅｃｏｓｔ ｅｆ ｆｅｃｔｉｖｅｐｒｏｃｅｓｓｉｎｇｔｅｃｈｎｏｌｏｇｉｅｓｏｆＡｌ/ＳｉＣＰｃｏｍｐｏｓｉｔｅｓｃｏｎ ｔｉｎｕｅｔｏｂｅａｋｅｙｒｅｓｅａｒｃｈａｒｅａ .Ｓｔｉｒｃａｓｔｉｎｇｉｓｔｈｅｍｏ…     

颗粒形状对铝基复合材料热残余应力影响的有限元分析

通过复合材料显微组织观察，建立了平面应力状态的复合材料组织模型，利用有限元方法对Al2O3p/2024Al复合材料和SiCp/2024Al复合材料淬火过程的热应力进行了数值模拟，研究了颗粒形状对铝基复合材料淬火处理过程下热残余应力的影响．结果表明，由于增强颗粒与铝基体之间的热膨胀系数差异较大，淬火处理后颗粒和基体的界面附近产生很大的热残余应力场，同时基体发生塑性应变．     

Fabrication and properties of Al matrix composites strengthened by in situ alumina particulates

New aluminum matrix composites strengthened by Al2O3 particulates through stirring cast by adding NH4Al（SO4）2 to the molten aluminum have been fabricated. TEM observation shows that in-situ Al2O3 particulates are generally spherical and they are uniformly distributed in the Al matrix. Dry sliding wear test results show that the volume loss of the unreinforced Al matrix is about three times that of the Al2O3 reinforced metal matrix composite （MMC） and the volume loss of the MMC fabricated by adding Al2O3 is larger than that of the MMC by adding NH4Al（SO4）2. Lubricating sliding wear test results show that the volume loss of the MMCs increases more slowly than that of the matrix with the increasing of the load.     

Reactive processing and mechanical properties of Al/SiCP composite

The reactive process for Al/SiC_P composite was studied. SiC particles were in-situ coated by the exothermal reaction of SiC-Ti powder compact in Al melt bath, and easily incorporated into Al melt. The detailed study was carried out to understand the microstructures of the reacted SiC particles. During the reaction and consequent mixing, the successive processes include in-situ coating on the reacted SiC particles, coat dissolution and SiC_P splitting. The tensile mechanical properties of 6013Al/SiC_P composite processed by the present technology showed that the reacted SiC_P considerably reinforced the 6013 matrix. Foundation item: The Key Program of the 9th Five-year Plan of China(No. 95-YS-005) Biography of the first author: CHEN Kang-hua, professor, born on Aug. 30, 1962, received Ph. D degree in 1991, majoring in Al alloy, Al matrix composite and powder metallurgy.     

熔盐法制备Al_2O_3粒子增强铝基复合材料的工艺研究

用碱性熔盐作为载体将Al_2O_3粒子较均匀地添加到铝合金熔体中是获得Al_2O_3粒子增强铝基复合材料的新方法。本文对比了熔盐种类、配比、加入方法及Al_2O_3粒子大小对其在铝基体中分布均匀性的影响,测定了Al_2O_3粒子强化铝基铸选复合材料的机械性能。     

Thermodynamics and kinetics of in-situ formation of TiAl3/7075 composites

The thermodynamics and kinetics of the reaction between Titanium powder and 7075 aluminum alloy were investigated to assess the possibility of preparing TiAl₃/7075 composites by in-situ synthesis method. Results show that Ti and Al melt can form TiAl₃ spontaneously, which is considered as a reinforced phase of the matrix. Measurements such as XRD, SEM, and EDX were performed to characterize the as-synthesized samples, and results confirmed the formation of TiAl₃ in aluminum matrix composites. The reactive kinetics was controlled by three main factors, which are the system temperature, particle size of Ti, and the thickness of external diffusion layer.     

颗粒簇增强金属基复合材料的细观力学行为

基于SiC／Al基复合材料中的SiC颗粒簇周期性排布假设，通过三维有限元体胞方法，探讨了不同堆积形式下的颗粒簇微结构对基体材料中热残余径向应力的分布，所得结果对于深入理解金属基复合材料的损伤过程有参考价值。     

Effect of electromagnetic stirring on the microstructure and wear behavior of iron-based composite coatings

The effect of electromagnetic stirring on the microstructure and wear behavior of coatings has been investigated. A series of iron-based coatings were fabricated by the plasma-transferred arc cladding process by applying different magnetic field currents. The microstructure and wear resistance of the composite coatings were characterized by scanning electron microscope (SEM), energy dispersive X-ray analysis (EDAX), X-ray diffraction (XRD), and wet sand rubber wheel abrasion tester. The experimental re- sults showed that the microstructure of the coatings was mainly the γ-Fe matrix and (Cr, Fe)7C3 carbide reinforced phase. The coatings were metallurgically bonded to the substrate. With increasing magnetic field current, the amount of the block-like (Cr, Fe)7C3 carbide reinforced phase increased at first, reached a local maximum, and then decreased sharply. When the magnetic field current reached 3 A, the block-like (Cr, Fe)7C3 carbides with high volume fraction were uniformly distributed in the matrix and the coating displayed a high microhardness and an excellent wear resistance under the wear test condition.     

Microstructure and Tribological Behavior of Al_2O_3 Particle Reinforced Al Matrix Composites Fabricated by Spark Plasma Sintering

Nanoparticles and microparticles reinforced Al matrix composites were fabricated by spark plasma sintering, and the microstructure and tribological properties were investigated systemically. The nano-Al_2O_3 particle and micro-Al_2O_3 particle uniformly dispersed in Al matrix composites. The introduction of nanoparticles is beneficial to the decrease of friction coefficient and wear rate, while microparticles are responsible to the high friction coefficient, resulting in the abrasive wear. With the introduction of both nanoparticles and microparticles, their synergic effect will lead to the variation of tribological behavior.     

制取钢基颗粒铸造复合材料喷吹工艺方法研究

本文研究了制取钢基颗粒铸造复合材料的工艺方法。采用中锰奥氏体钢为基体,以氩气为载体,把Al_2O_3或ZrO_2颗粒喷射到钢液中,研究了工艺参数间关系及其影响。     

原位合成Al_2O_3/FeAl复合材料的组织与性能

利用Fe-Al-Fe2O3体系的放热反应,原位热压合成了Al2O3/FeAl复合材料.借助XRD和SEM等研究了复合材料的物相组成和显微结构,以及Al2O3生成量对复合材料显微结构和力学性能的影响.结果表明:经1 250℃保温1.5h热压烧结的块体材料主要由FeAl及少量Al2O3相构成,FeAl基体为片层结构,增强相Al2O3分散在基体和晶界处.随着Al2O3含量的增加,基体晶粒尺寸明显减小,同时对材料起增强增韧作用.在Al2O3含量为1.2wt%时,试样的抗弯强度达到最大值1 329.22MPa;在Al2O3含量为0.8wt%时,试样的断裂韧性达到最大值29.95MPa·m1/2.此值正好处于金属与陶瓷材料性能链的断缺处.因此,本研究结果对于完善材料性能体系具有重要意义.     

In situ prepared Al-Si alloy matrix composites reinforced by γ-Al2O3p

A γ-Al2O3 particles reinforced Al-Si alloy matrix composite was fabricated by adding NH4Al(SO4)2 to molten aluminum alloy. TEM observation shows that in-situ γ-Al2O3 particles are generally spherical and uniformly distributed in the matrix. The results of dry sliding wear tests show that the wear resistance of the composites increases with increasing mass fraction, and the volume loss is considerably lesser than that of the matrix and is lesser than that of the composites by adding γ-Al2O3 particles directly.     

冷却速度对SiCp/2024Al热残余应力影响的数值模拟

针对冷却速度对SiCp／2024Al复合材料热残余应力的影响，通过复合材料显微组织观察，根据复合材料的形貌特征，建立了平面应力状态的复合材料组织模型，利用有限元方法对SiCp／2024Al复合材料淬火和退火过程的热应力进行了数值模拟．结果表明，由于SiC增强颗粒与铝基体之间的热膨胀系数差异较大，热处理后颗粒和基体的界面附近产生很大的热残余应力场，同时基体发生塑性应变；冷却速度对复合材料热残余应力没有明显影响．     

AlTiC增韧补强氧化铝基陶瓷材料磨擦磨损性能

采用热压烧结方法制备了氧化铝／碳化钛复合陶瓷，对材料的摩擦因数和磨损率进行测量，研究了AlTiC中间合金增韧补强氧化铝陶瓷摩擦磨损行为与机制，探讨了氧化铝基精密结构陶瓷的摩擦磨损特性以及力学性能和微观结构对摩擦磨损特性的影响。结果表明，在室温和干摩擦条件下，滑动摩擦因数随法向载荷和转速的增加有下降趋势，室温下新型氧化铝基复相陶瓷材料的磨损机制以微观切削为主。     

颗粒增强金属基复合材料的研究(一)

金属基复合材料是由陶瓷颗粒或纤维(比如SiC，Al2O3，TiC，TiB等)增强金属或合金基体而得到的，具有高的比刚度、比强度、耐磨性和高温性能，且具有可设计性，是一类高性能先进材料，在航空、航天、汽车等领域具有良好的应用前景。综述了金属基复合材料的类型、成型方法及主要强化性能指标，阐述了颗粒强化金属基体的机理，提出了用纳米颗粒强化金属基体的新思路，简要介绍了实验方法，预测了性能改善程度，并阐述了其发展前景。     

Thermodynamic analysis of the formation of <Emphasis Type="Italic">In-situ</Emphasis> reinforced phases in cast Al-4.5Cu alloy

The thermodynamic analysis of the formation of in-situ reinforced phases in （TiB2＋Al3Ti）/Al-4.5Cu composites prepared by mixed salts reaction was conducted, and heat changes of mixed salts system were analyzed by differential thermal analysis（DTA）.The results show that although TiB2 possesses the strongest formation ability in Al-Ti-B ternary system, [Ti] is relatively excessive in the in-situ reaction and it combines with Al to form AlaTi phase. The reinforced phases are TiB2 and AlaTi in the produced composites due to the reaction taking place to form reinforced phase with the addition of mixed salts into Al-4.5Cu melt between 900 ℃ and 1 032 ℃.     

掺杂对Al_2O_3/TiAl复合材料性能的影响

本研究采用Ti-Al-TiO2-La2O3体系,通过热压烧结工艺原位合成了Al2O3/TiAl复合材料.借助X射线衍射(XRD)、扫描电镜(SEM)等分析研究了材料的物相组成和微观组织结构,同时分别将掺杂La2O3和掺杂Fe2O3对合成Al2O3/TiAl复合材料微观结构和力学性能的影响进行了对比.结果表明:掺杂La2O3合成的Al2O3/TiAl复合材料基体尺寸相对掺杂Fe2O3合成产物较小,分散更加均匀,致密度更高.当La2O3掺杂量为3.93wt%时,Al2O3/TiAl复合材料的抗弯强度和断裂韧性达到最大值,分别为701.95MPa和7.79MPa·m1/2.由于稀土氧化物具有对基体和增强颗粒的净化,细化晶粒等作用,因此提高了TiAl基体与Al2O3增强颗粒结合强度,所以掺杂La2O3合成材料的力学性能相比掺杂Fe2O3合成的产物较高.     

Alignment of primary Al<Subscript>3</Subscript>Ni phases in hypereutectic Al-Ni alloys with various compositions under high magnetic fields

Al-Ni hypereutectic alloys with various compositions were solidified under various magnetic field con- ditions to investigate the alignment of primary Al3Ni phases. The results showed that the application of high magnetic fields could improve the homogeneity of the primary Al3Ni phase distribution and induce the alignment of primary Al3Ni phases in the direction perpendicular to the magnetic field direction to form chain-like structures. However, the alignment was different from the orientation of the Al3Ni...