Ti2SnC颗粒增强铜基复合材料的力学性能

用粉末冶金方法制备了一种以三元层状陶瓷Ti2SnC为增强相的Cu/Ti2SnC复合材料，研究了增强相的含量对复合材料的显微结构和硬度、拉伸强度等力学性能的影响。结果表明，Ti2SnC对于铜是一种有效的增强相，当Ti2SnC的体积含量为20％（体积分数，下同）时增强效果最佳，屈服强度和拉伸强度分别达到319MPa和440MPa，是相同工艺条件下制备的纯铜的屈服强度和拉伸强度的4倍和2倍，并保持12％的延伸率。强化是由于铜基体晶粒的细化和位错塞积引起的。     

烧结温度对Ti2SnC/TiC复合材料摩擦磨损特性的影响

以Ti、Sn和C的单质粉体为原料,通过放电等离子烧结技术合成Ti2SnC和TiC的复合材料.研究烧结温度对Ti2SnC/TiC复合材料组织和摩擦磨损等性能的影响.结果表明,烧结温度低于700℃时,烧结块体主要由Ti6Sn5相组成;烧结温度升高到900～1000℃时相组成变为Ti2 SnC+ TiC;当温度高于1000℃时Ti2SnC有分解迹象.1000℃烧结的复合材料具有较低的硬度和较小的摩擦因数.     

热爆反应合成Ti2SnC材料及反应机制的研究

采用热爆反应技术制备Ti2SnC材料,研究了两种不同原料对反应合成Ti2SnC的影响,探讨了反应合成机制.结果表明,2Ti/Sn/C粉体反应合成产物的主相为TiSnx、TiC,产物中Ti2SnC含量较少,同时残留少量未反应完全的Sn.Ti/Sn/TiC粉体反应合成的产物主相为Ti2SnC,同时含有少量未反应完全的Sn和TiC.热爆反应合成Ti2SnC的反应机制:Ti2SnC由两种反应路径合成,一种是TiSnx与TiC发生固相反应合成的Ti2SnC;另一种是Ti-Sn共晶液相与TiC发生反应合成的Ti2SnC.     

Al2O3颗粒增强铜基复合材料的组织

采用烧结－加压－烧结－加压的工艺制取了Ａｌ２Ｏ３－Ｃｕ复合材料,并对其金相组织及界面进行了观察与分析,证明了工艺是可行的,二次烧结加压有利于增强粒于均匀分布,在复合材料界面处存在的着Ａｌ％的浓度梯度,在ＣｕＡｌＯ２生成的迹象。     

烧结温度对MAX/Cu复合材料的组织及性能影响

以一种典型的MAX相材料Ti₃AlC₂为原料,采用粉末冶金无压烧结的方式,压坯压力选用500 MPa,烧结时间为1 h,分别选用800、900、1 000、1 100、1 200℃5个烧结温度制备了MAX/Cu复合材料。通过对样品的金相、电导率与显微硬度等测试,探讨了不同烧结温度下MAX/Cu复合材料的组织及其性能变化。结果表明,无压烧结最佳烧结温度为1 100℃,可以得到综合性能最佳的复合材料,硬度、致密度和导电率分别达到330 HV、99.5%以上和4.6 m S/m。     

ZrB2-SiC-AIN陶瓷基复合材料的组织及性能

选用AIN作烧结助剂，采用热压烧结技术制备了ZrB2＋20％SiC＋η％AIN陶瓷基复合材料。利用SEM等手段对其组织进行了分析，并对其力学性能和高温烧蚀性能进行了分析测试。     

铜包覆Ti2AlC增强铜基复合材料的制备及性能

通过化学镀技术在Ti₂AlC粉体表面镀上一层金属铜,然后以铜粉、镀铜Ti₂AlC粉为原料,采用烧结法制备了10%Ti₂AlC/Cu复合材料。结果表明：化学镀铜溶液pH为11～12时,Ti₂AlC粉体表面的铜镀层光滑致密、不易脱落。10%Ti₂AlC/Cu复合材料的组织分布均匀,镀铜Ti₂AlC颗粒与铜基体结合紧密;复合材料相对密度为94.31%,导电性能和硬度相对于纯铜稍有下降;复合材料的平均摩擦系数随着载荷的增加稍微下降,从10 N时的0.4862到30 N时的0.3858,相对于纯铜有明显降低;复合材料的磨损率随着载荷增加逐渐下降,从10 N时的0.208 g·N^-1·m^-1变为30 N时的0.147 g·N^-1·m^-1。表明复合材料具有较好的耐磨性。     

放电等离子烧结Ti/Al_2O_3复合材料机制及性能

利用放电等离子烧结技术制备了Ti/Al_2O_3复合材料,并探讨了其烧结机理,对复合材料性能进行测试.结果表明,Ti/Al_2O_3导电网络结构的形成,有利于在烧结过程中形成的"电容器"瞬间击穿,使Al_2O_3遭到轰击而产生放电离子,活化Al_2O_3晶粒,降低烧结温度;当Ti 含量为40%(体积分数,下同)时复合材料的相对密度、弯曲强度、断裂韧性和显微硬度分别为99.74%、1002 MPa、19.73 MPa·m~(1/2)和18.14 GPa;裂纹的桥联、偏转是试验材料力学性能得以提高的主要原因.     

Ti元素对Ti3SiC2在铜基复合材料中的分解抑制研究

三元层状Ti₃SiC₂陶瓷是一种新型的陶瓷材料,具有密度低、熔点高等特点,作为增强相可以明显改善Ti₃SiC₂/Cu复合材料的力学性能和摩擦磨损性能。然而,在烧结过程中Ti₃SiC₂发生分解,导致复合材料组织与性能发生改变。为了抑制Ti₃SiC₂的分解,提高复合材料性能,对Ti₃SiC₂颗粒表面进行多弧离子镀Ti改性,制备了界面性能优良,Ti₃SiC₂颗粒未分解的复合材料。研究了Ti₃SiC₂在复合材料的分解和Ti元素对其分解的抑制机理,分析了不同含量Ti₃SiC₂的复合材料的组织演化。结果表明,对Ti₃SiC₂表面进行镀覆Ti元素可以有效抑制Ti₃SiC₂     

自蔓延高温烧结制备钛锡碳结合剂金刚石复合材料

采用自蔓延高温烧结(SHS)技术,以Ti/Sn/石墨/Diamond粉体为原料,制备了Ti2SnC结合剂金刚石复合材料。研究了金刚石粒径和质量分数对试样的物相组成与金刚石表面显微形貌的影响。研究结果表明:2Ti/Sn/C试样反应后生成Ti2SnC,同时生成TiC,剩余一定量Sn。添加不同粒度(M10/20、120/140、80/100和30/40)的金刚石后,Ti2SnC含量有所下降。金刚石表面会形成TiC与Sn构成的涂层。随着金刚石质量分数(120/140)的增加,样品中Ti2SnC的形成相应地受到抑制,同时金刚石与基体结合也变差,当金刚石质量分数为40%时,金刚石表面无法形成良好的涂覆。     

Effect of powder mixing process on the microstructure and thermal conductivity of Al/diamond composites fabricated by spark plasma sintering

Two powder mixing processes, mechanical mixing (MM) and mechanical alloying (MA), were used to prepare mixed Al/diamond powders, which were subsequently consolidated using spark plasma sintering (SPS) to produce bulk Al/diamond composites. The effects of the powder mixing process on the morphologies of the mixed powders, the microstructure and the thermal conductivity of the composites were investigated. The results show that the powder mixing process can significantly affect the microstructure and the thermal conductivity of the composites. Agglomerations of the particles occurred in mixed powders using MM for 30 min, which led to high pore content and weak interfacial bonding in the composites and resulted in low relative density and low thermal conductivity for the composites. Mixed powders of homogeneous distribution of diamond particles could be obtained using MA for 10 min and MM for 2 h. The composite prepared through MA indicated a high relative density but low thermal conductivity due to its defects, such as damaged particles, Fe impurity, and local interfacial debonding, which were mainly introduced in the MA process. In contrast, the composite made by MM for 2 h demonstrated high relative density and an excellent thermal conductivity of 325 W·m-1·K-1, owing to its having few defects and strong interfacial bonding.     

原位合成TiC和TiB增强钛基复合材料的微观结构与力学性能

利用钛与Ｂ４Ｃ之间的自蔓延高温合成反应经普通的熔钐工艺原位合成制备了ＴｉＣ、ＴｉＢ增强的钛基复合材料。光学金相、ＥＰＭＡ、ＴＥＭ和Ｘ射线衍射的研究结果表明：存在匠两种不同形状的增强体,即短纤维状ＴｉＢ晶须和等轴、近似等轴状ＴｉＣ粒子。ＴｉＢ、Ｔｉ基体界面洁净,没有明显的界面反应,而ＴｉＣ、Ｔｉ基体界面有非化学配比的ＴｉＣ过度层存在。由于增强体承受载荷,基体合金晶粒细化以及高密度位错的存在,制备钛基     

Ti3AlC2颗粒含量对Ti3AlC2/ZA27 复合材料性能的影响

通过无压烧结技术和机械合金化技术,在烧结温度为870 °C,保温时间为2.5h的工艺条件下,制备了四种不同体积含量的Ti3AlC2 颗粒含量的Ti3AlC2/ZA27复合材料。研究了Ti3AlC2 颗粒含量对Ti3AlC2 /ZA27复合材料的硬度,密度,拉伸强度和弯曲强度的影响。结果表明界面处的微弱的化学反应有助于提高复合材料的界面结合能力,进而提高Ti3AlC2 /ZA27复合材料的机械性能。此外,随着Ti3AlC2 颗粒含量增多,Ti3AlC2 /ZA27复合材料的硬度和力学强度都随之增大,这主要归因于纳米尺度的Ti3AlC2颗粒的弥散增强结果。然而,随着Ti3AlC2 颗粒的增加到40 vol. %, 由于孔隙的增多,Ti3AlC2 /ZA27复合材料的硬度和力学强度又出现下降。对比制得的四种Ti3AlC2 /ZA27复合材料,30Ti3AlC2/ZA27复合材料拥有最大的抗拉强度、抗弯曲强度以及维氏硬度,分别为310 MPa,528 MPa 和1.24 GPa. 这些优异的性能除了归因于良好的界面结合,还归因于Ti3AlC2颗粒的细晶强化和弥散强化作用。     

钛对碳纳米管增强铝基复合材料组织与性能的尺寸效应

通过粉末冶金的方法,制备了致密和较高强度的CNT/Al复合材料,并系统地研究了在制备粉末阶段时引入不同粒径的钛粉后,对复合材料的组织结构与力学性能的影响。结果表明,在一定范围内,钛颗粒尺寸与制备的CNT-Ti/Al复合材料力学性能成反比。当加入的钛颗粒粒径为80 nm时,CNT-Ti/Al复合棒材力学性能最佳。其主要原因包括两个方面:一是钛颗粒有助于碳纳米管的分散,同时自身作为一种第二相强化基体;二是制备过程的热反应,使复合材料组织中生成了一种核壳结构,极大地增强了其界面结合与碳纳米管的载荷转移。     

Effect of particle size on the microstructure and thermal conductivity of Al/diamond composites prepared by spark plasma sintering

Spark plasma sintering (SPS) was used to fabricate Al/diamond composites. The influence of diamond particle size on the microstructure and thermal conductivity (TC) of composites was investigated by combining experimental results with model prediction. The results show that both composites with 40 μm particles and 70 μm particles exhibit high density and good TC, and the composite with 70 μm particles indicates an excellent TC of 325 W·m⁻¹·K⁻¹. Their TCs lay between the theoretical estimated bounds. In contrast, the composite with 100 μm particles demonstrates low density as well as poor TC due to its high porosity and weak interfacial bonding. Its TC is even considerably less than the lower bound of the predicted value. Using larger diamond particles can further enhance thermal conductive performance only based on the premise that highly dense composites of strong interfacial bonding can be obtained.     

Effect of processing parameters on the microstructure and thermal conductivity of diamond/Ag composites fabricated by spark plasma sintering

Diamond/metal composites with 50 vol.% diamond have been produced by spark plasma sintering (SPS) using pure Ag as a matrix and diamond particles as reinforcement. Three kinds of powder mixing processes were used to prepare the mixture of diamond/Ag powders: dry mixing without milling medium, wet mixing and magnetic blending. Subsequently, they were all consolidated by SPS at various processing parameters to produce bulk diamond/Ag composites. Then samples were heat treated in order to obtain a higher thermal conductivity. The effect of processing parameters on the morphologies of the mixed powders, the microstructure and the thermal conductivity of the composites were investigated by comparing the experimental data. It reveals that particles were easy to agglomerate and the distribution of mixed powders was inhomogeneous by dry mixing method, and wet mixing method is too complex. The most favorable mixing process is magnetic blending by which the powders can be homogenously mixed and the composites prepared by optimized SPS processing parameters can obtain the highest relative density and the best thermal conductivity among the composites prepared by different processes. The magnetic blending diamond/Ag composites even have a 23% increase in thermal conductivity compared with pure silver sintered by SPS.     

导电陶瓷Ti3SiC2-Cu-C复合材料的制备与性能研究

用粉末冶金法制备了一定含量的镀铜和不镀铜Ti3SiC2-Cu-C复合材料,以及Cu-C复合材料,对它们的物理和力学性能进行了测试,并在滑动速度为10m/s,载荷为4.9N的干摩擦条件下进行了36h磨损试验,结果表明:镀铜Ti3SiC2-Cu-C复合材料的导电性、硬度、抗弯强度和耐磨性优于不镀铜Ti3SiC2-Cu-C复合材料和Cu-C复合材料。     

热处理对金刚石/2024Al复合材料微观组织和热物理性能的影响

采用挤压铸造法制备粒径为5μm、体积分数为50%的金刚石/2024Al 复合材料。退火处理后对其金相组织界面反应、界面结合情况以及金刚石颗粒的内部缺陷进行观察与分析,并对其热物理性能进行测试与研究。结果表明,金刚石/2024Al 复合材料的组织致密,无明显的气孔、夹杂等缺陷;颗粒为不规则多边形,有棱角,分布比较均匀。透射电镜观察表明,部分金刚石颗粒内部有位错和层错存在,而2024Al 基体中的位错密度较大,金刚石/2024Al界面处有较多的界面反应物生成,可能为Al2Cu。复合材料在20~100°C温度区间内的平均热膨胀系数为8.5×10-6°C-1,退火处理的复合材料其热膨胀系数有一定程度的降低;随着温度的升高,复合材料的平均热膨胀系数也呈现增加的趋势。复合材料的热导率约为100 W/（m·K）,退火处理能够提高复合材料的热导率。     

TiB2/Cu复合材料用于电火花加工电极的可行性探讨

从分析电火花加工对电极材料的基本要求入手，结合TiB2／Cu复合材料在目前制备工艺条件下所获得的电学、力学性能等特性，采用对比研究的方法，探讨将其作为电火花加工电极材料的可行性。