热处理对变形纳米Al2O3颗粒增强铝基复合材料硬度和耐磨性的影响

采用现代冶金分析、硬度测定和磨损性实验研究了不同热处理条件下变形态纳米Al<,2>O<,3>颗粒增强铝基复合材料的性能.结果表明:形变热处理可以大幅提高该材料的硬度和耐磨性;尤其是在510℃×3 h固溶+120℃×24 h时效状态下复合材料的耐磨性最好,磨损量仅为相同磨损条件下基体材料的8.8%,摩擦系数仅为0.18;但随固溶温度的升高,时效后复合材料的硬度的提高幅度有下降趋势.     

热处理对挤压铸造TiB2P/6061Al复合材料组织与性能的影响

采用挤压铸造法制备了不同体积分数的TiBzv／6061Al复合材料，利用扫描电镜、透射电镜、硬度计、三点弯曲等手段对复合材料的组织与力学性能进行了研究，分析了热处理工艺对其组织性能的影响。结果表明：不同的热处理条件下TiB2P／6061Al复合材料的组织不同：退火态时观察到再结晶晶粒和少量位错：时效态时观察到大量的位错和析出相，界面产物尺寸比退火态时相对大些，且在界面附近的基体中存在明显的无析出区。热处理状态对弹性模量的影响不大，但对材料的硬度和抗弯强度影响较大。45％TiB2v／6061Al复合材料时效处理后硬度和抗弯强度分别比退火态时提高了40％和23％。     

热处理对SiCp/Fe复合材料组织性能的影响

采用电流直加热动态热压烧结工艺制备了10vol%SiCp/Fe复合材料,研究了热处理对SiCp/Fe复合材料硬度、冲击性能及显微组织的影响。结果表明:正火对SiCp/Fe复合材料的硬度和冲击性能无显著影响,而通过淬火+回火热处理,复合材料的硬度和冲击性能可获得显著提高。经850℃淬火+650℃回火热处理后,SiCp/Fe复合材料维氏硬度和冲击吸收能量可达658. 4 HV5和95. 2 J,与未热处理试样相比,维氏硬度提高了29. 9%,冲击吸收能量提高了43. 6%。显微观察表明,经850℃淬火+650℃回火热处理SiCp/Fe复合材料基体显微组织为铁素体和珠光体,未见孔洞缺陷。     

水下搅拌摩擦加工制备CoCrFeNiMn/6061Al复合材料组织和性能研究

采用水下搅拌摩擦加工制备CoCrFeNiMn高熵合金颗粒增强6061-T6基复合材料，研究了时效热处理对CoCrFeNiMn/6061Al复合材料微观组织、显微硬度和磨损性能的影响。采用扫描电镜和电子背散射衍射技术对复合材料的微观组织进行了表征，采用显微硬度和磨损实验对复合材料的性能进行了评价。结果表明，经5道次搅拌摩擦加工后，CoCrFeNiMn高熵合金颗粒均匀分布在Al基体中，且与基体界面结合良好，无明显扩散层。时效热处理后，CoCrFeNiMn高熵合金颗粒与基体界面出现厚度约为200 nm的扩散层，复合材料的平均显微硬度达到120.0 HV,比Al基体提高了27.7%。与Al基体相比，复合材料的平均摩擦因数从0.4491升高至0.4855。时效热处理后，复合材料的平均摩擦因数降低至0.3188,主要磨损机制为磨粒磨损。     

热处理温度对炭/炭复合材料性能的影响

利用热梯度化学气相沉积工艺制备了炭／炭复合材料,研究了热处理温度对炭／炭复合材料石墨化度、硬度、抗弯强度和摩擦性能的影响。结果表明：石墨化度随着热处理温度的升高而增大,炭,炭复合材料石墨化的能垒在2200℃附近;炭／炭复合材料的抗弯强度随着热处理温度的升高,先升高后降低,当热处理温度是2000℃时,所得材料的抗弯强度最高;炭／炭复合材料的硬度和摩擦系数随着热处理温度的升高而降低。     

自生TiC颗粒增强低合金钢基复合材料的组织

通过加入一定量的Mn、Si合金元素,使得TiC颗粒增强低合金钢基复合材料在湿砂型铸造条件下具有自淬火特性,获得单一马氏体组织或马氏体和珠光体的混合基体组织.经过热处理后,基体获得单一马氏体组织.含2.71% Ti的复合材料铸态最高硬度达到55 HRC,热处理硬度59.9 HRC,冲击韧度达到9.17 J/cm2.     

热处理对TiCp/Fe复合材料基体组织与力学性能的影响

通过不同的热处理工艺改变原位TiCp／Fe复合材料的基体组织，探讨了原位TiCp／Fe复合材料不同基体组织与性能的关系。试验结果表明：在热处理过程中基体组织明显改变，TiC增强相不发生变化。退火处理降低材料的硬度，提高材料的韧性。淬火 低温回火处理使材料的强度和硬度提高，而韧性没有明显的下降。采用等温淬火工艺，可使TiCp／Fe复合材料具有最好的综合力学性能。     

热处理对SiCp/Al-Cu-Mg基复合材料力学性能的影响

用粉末冶金法制备了SiCp/Al-Cu-Mg基复合材料,研究了SiC颗粒体积分数、Mg在基体合金中的含量(质量分数)以及热处理工艺对SiCp/Al-Cu-Mg复合材料的力学性能的影响.结果表明,热处理工艺、SiC颗粒的加入和在基体合会中的Mg含量,都能明显提高复合材料的硬度和强度.9v01%SiC/Al-4wt%Cu-1.2wt%Mg复合材料的力学性能最好,其硬度和强度由热处理前的101.3 HV0.02和285 MPa提高到热处理后的151.5 HV0.02和372 MPa.     

镁/铝层状复合材料的扩散连接制备及界面特性

采用扩散连接制备了镁/铝层状复合材料,进而采用热处理改善界面结合性能,最后利用纳米压痕技术初步研究了复合材料的界面结合状况。结果表明,采用400℃/30MPa/10min、400℃/40MPa/10min和400℃/30MPa/20min3种条件均可获得连接较好的层状复合材料,但400℃/30MPa/10min条件下扩散层不明显;利用热处理可以改善界面结合状况,对于扩散层明显的复合材料,热处理可以大大增加扩散层厚度;扩散层的纳米硬度比基体高约3倍,弹性模量介于镁合金的与铝合金的之间。     

高性能铸造截齿合金刀头材料的研究

镶铸截齿是降低截齿制造成本,使用寿命提高的有效途径之一.为提高镶铸截齿的使用寿命,需要超高硬度的铸造合金材料.本文作为截齿合金刀头材料研究了TiC/Fe复合材料,在原有的高耐磨材料的基础上,添加适量Ti,形成自生TiC颗粒增强复合材料,经热处理后硬度达到了HRC70,而且材料对热处理温度敏感性下降,便于镶铸截齿整体的热处理.同时研究了合金成分和热处理温度对材料硬度的影响规律.     

(TiB2+SiC)/ZL109复合材料的制备及其力学性能

采用搅拌铸造和原位反应合成相结合的方法制备出(TiB2 SiC)/ZL109复合材料.对该复合材料的显微组织观测表明,SiC颗粒与TiB2颗粒分布较均匀.通过对材料的室温拉伸性能及硬度测试,发现TiB2、SiC两相颗粒增强AlSi基复合材料的硬度明显比单一颗粒增强复合材料提高,而其拉伸强度也略有提高,弥补了单一SiC颗粒增强铝基复合材料UTS降低的不足.(TiB2 SiC)/ZL109复合材料较基体合金ZL109硬度提高了34.8%.     

反复塑性变形对SiC_p/AZ31镁基复合材料组织和性能的影响

采用反复塑性变形(RPW)技术,结合挤压工艺制备出SiC颗粒增强AZ31镁基复合材料,研究了循环次数(RPW次数)对SiC_p/AZ31镁基复合材料显微组织和性能的影响.结果表明,反复塑性变形具有明显的AZ31基体晶粒细化、SiC_p细化和分散作用,能显著提高SiC_p/AZ31复合材料的抗拉强度和硬度,并改善其塑性.在SiC_p的体积分数为4%时,经RPW为300次的热挤压后,AZ31基体晶粒粒径达到最小值20 μm,SiC_p被粉碎成3 μm以下的微粒,且弥散分布于合金基体中,复合材料的室温抗拉强度和硬度(HV)达到或接近最大值,分别为359 MPa和107.     

SiC颗粒增强铝基复合材料物理及力学性能研究进展

SiC颗粒增强铝基复合材料既保持了金属特有的良好延展性、传热等特点,又具有陶瓷的耐高温性、耐磨损的要求。综述了SiC颗粒增强铝基复合材料的物理及力学性能,SiC颗粒增强铝基复合材料强化的物理模型主要有两种,即剪切滞后模型与Eshelby理论。     

纳米SiC颗粒增强ADC12铝基复合材料的制备及性能

采用机械搅拌和超声分散相结合的方法制备出了纳米SiC颗粒增强ADC12铝合金基复合材料,并对制备出的复合材料进行微观结构分析和力学性能测试.结果表明,与基体合金相比,当纳米SiC颗粒的含量为2.0%时,所制得的复合材料的抗拉强度、弹性模量、断面收缩率及硬度分别提高23%、43%、160%和7.4%.用扫描电镜对试样拉伸断口的形貌和SiC颗粒的分散情况进行观察,发现纳米SiC颗粒在基体内呈均匀的弥散分布,没有发现大的团聚.同时,纳米SiC颗粒的均匀分布起到了阻碍或者阻止裂纹产生和扩展的作用.     

Investigation on the constitution and mechanical characteristic of composite containing silicon-carbide produced by electroless co-deposition

The constitution and mechanical characteristics of the composites containing silicon carbide and Ni-P alloy matrix produced by electroless co-deposition were investigated in this article. The experimental results indicate that SiC particles with high hardness obviously strengthen the Ni-P alloy matrix, leading to an increase in both the hardness and surface roughness of the composites in comparison with pure Ni-P alloy. The hardness of the composites reaches the maximum value when heat treated at 673 K for 1 h. During the friction and wear process, the wear resistance of SiC composites is higher than that of Ni-P alloy and hard chromium plating, although the friction coefficient of the composite is comparatively high, which is attributed to the worn-resistant hard phase.     

The effect of primary and secondary processing on the abrasive wear properties of compocast aluminum 6061 alloy matrix composites

In this present work, the compocasting method was used to produce Aluminum 6061 alloy matrix composites reinforced SiC particles with a variety of particle average sizes of 1, 5, 20 and 50 μm. The influences of particle volume fraction of metal matrix composites on the dry sliding wear behaviour have been investigated. The acceptable quality of the fabricated composites calls for a proper selection of process parameter such as pouring temperature, stirring speed, stirring time, preheat temperature of reinforcement, minimum level of the porosity and prevention of the chemical reaction between reinforcement and matrix. Experimental test was carried out on the porosity and hardness of the composites. A pin-on-disc wear test was used to assess the effect of SiC content, SiC size and secondary mechanical processing with different rolling reductions on wear characteristics of Al matrix composites. It is noted that the particle distribution in the cold rolled composites is much more uniform than the as-cast one.     

Microstructures and mechanical properties of Al 2519 matrix composites reinforced with Ti-coated SiC particles

Ti-coated SiC_p particles were developed by vacuum evaporation with Ti to improve the interfacial bonding of SiC_p/Al composites. Ti-coated SiC particles and uncoated SiC particles reinforced Al 2519 matrix composites were prepared by hot pressing, hot extrusion and heat treatment. The influence of Ti coating on microstructure and mechanical properties of the composites was analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that the densely deposited Ti coating reacts with SiC particles to form TiC and Ti₅Si₃ phases at the interface. Ti-coated SiC particle reinforced composite exhibits uniformity and compactness compared to the composite reinforced with uncoated SiC particles. The microstructure, relative density and mechanical properties of the composite are significantly improved. When the volume fraction is 15%, the hardness, fracture strain and tensile strength of the SiC_p reinforced Al 2519 composite after Ti plating are optimized, which are HB 138.5, 4.02% and 455 MPa, respectively.     

Aging behavior of nano-SiCp reinforced AZ61 magnesium matrix composites

The mechanical properties of magnesium matrix composties can be further improved by aging treatment.To study the aging behavior of SiC particles reinforced AZ61 magnesium matrix composites fabricated by ultrasonic method,an investigation has been undertaken by means of Vickers hardness measurement,scanning electron microscopy (SEM) and energy spectrum analyzing apparatus.The box-type heat treatment furnace was used in the study.The results showed that no discontinuous cellular precipitation is observed at the grain boundaries in the magnesium matrix of the composite while the Mg17Al12 preferentially precipitates in the matrix.The time to reach the peak hardness for AZ61 alloy or SiCp/AZ61 magnesium matrix composites is reduced with the increase of aging temperature.At the same temperature,the composite exhibit an accelerated aging manner but lower aging efficiency,compared with the unreinforced matrix alloy.The microhardness of the composite is higher than that of the unreinforced matrix alloy,because that the SiC particles distributes homogeneously in the matrix alloy under the ultrasonic processing condition.     

颗粒增强Al－4％Mg复合材料中显微孔隙的分析

探讨了Ａｌ２Ｏ３、ＳｉＣ、ＳｉＯ２等三种颗粒增强Ａｌ－４％Ｍｇ复合材料凝固组织中显微孔隙的形成规律．结果表明：前者显微孔隙是由Ａｌ２Ｏ３颗粒加入导致熔体粘度增加、颗粒堵塞枝晶间的补缩流动通道以及颗粒与基体合金的热膨胀系数的差异三种因素所引起；第二种材料由于气孔易在ＳｉＣ颗粒表面形核，或者ＳｉＣ颗粒与基体结合较弱，使得该复合材料比前者易形成显微孔隙；第三种复合材料，是由于ＳｉＯ２颗粒与基体间发生了界面反应，一定量的Ｓｉ溶入了基体，增大了基体的凝固潜热，从而提高了基体合金凝固时的补缩流动能力，所以ＳｉＯ２ｐ／Ａｌ－４％Ｍｇ复合材料的凝固组织比同样条件下Ａｌ２Ｏ３ｐ／Ａｌ－４％Ｍｇ和ＳｉＣｐ／Ａｌ－４％Ｍｇ复合材料致密。