超细SiC增强纯铝基复合材料显微组织与力学性能的研究

采用平均粒径为800nm的超细SiC颗粒作为增强体,制备含SiC体积分数为15%的铝基复合材料,研究烧结温度和强压处理对复合材料微观组织和力学性能的影响。研究表明,提高烧结温度可有效加速复合材料的致密化,与520℃下烧结制备的复合材料相比,610℃下烧结制备的复合材料具有更高的密度和较低的孔隙度,从而具有更高的硬度。610℃下烧结制备的复合材料的硬度为83.9HBS,远高于520℃烧结制备的复合材料的硬度(53.7HBS)。这主要是由于烧结温度的提高可加速原子扩散,有利于Al粉之间以及Al粉与SiC颗粒之间的结合,并改善界面结合情况。研究还表明,强压处理可以有效提高复合材料的致密度和降低孔隙的体积分数,610℃下烧结制备的复合材料经强压处理以后的密度为2.68g/cm3,接近于理论密度(2.78g/cm3),且硬度可达121HBS,抗拉强度、屈服强度和伸长率分别可达177.6MPa、168.6MPa和3.97%。     

纳米SiC颗粒增强2024铝基复合材料的力学性能研究

采用粉末冶金法制备了1%(体积分数)纳米SiC颗粒增强2024铝基复合材料,并研究了其力学性能。实验结果表明,1%纳米SiC颗粒增强2024铝基复合材料具有优良的室温力学性能,并且在200℃时表现了较好的高温性能,在315℃时强度下降。研究表明,纳米SiC可以增加增强粒子的表面积,减小增强粒子的颗粒间距,使大量弥散分布的纳米SiC颗粒起到钉扎位错的作用,而且可以细化2024铝基体的晶粒,因而表现了良好的力学性能。     

SiC颗粒增强铝基复合材料的制备工艺和性能研究

采用粉末冶金法制备SiCp/6061Al复合材料,研究热压温度、球磨工艺参数和SiC颗粒(SiCp)体积分数对SiC颗粒增强铝基复合材料性能的影响,测试其力学性能及物理性能,用扫描电镜对材料的微观组织和断口进行观察。结果表明:540℃是较适合的热压温度;随着SiCp含量的增加,复合材料的致密度、热膨胀系数下降,抗拉强度先提高后迅速降低。     

原位自生TiB+TiC增强Ti-Fe基复合材料微观组织和力学性能研究

以Ti粉、Fe粉和B_4C粉末为原料,采用冷等静压+高真空烧结方法制备了不同(TiB+TiC)增强相体积分数的Ti-Fe合金基复合材料(Fe元素质量分数为5%～15%),重点讨论了Fe含量和增强相对复合材料微观组织和力学性能的影响规律。结果表明,在1 150～1 250℃烧结温度下制备出Ti-Fe合金基复合材料致密度随Fe含量与增强相体积分数升高而降低。Fe含量增加使基体中α相层片状结构细化,而B_4C粉末的添加生成原位自生TiC颗粒和TiB纤维增强相,基体结构由层片状转变为等轴状。材料力学性能随Fe含量和增强相体积分数增加而提高。在1 150℃烧结制备的Ti-15%Fe-10vol%(TiB+TiC)复合材料硬度(HV)达到334,抗压强度达到2 040 MPa。     

原位合成SiC对铝基复合材料微观组织和力学性能的影响

以铝粉、硅粉、石墨粉为原料, 通过冷压真空烧结原位合成了含不同质量分数SiC颗粒的SiC/Al-18Si复合材料。利用X射线衍射仪, 扫描电子显微镜和能谱分析仪等设备手段表征了铝基复合材料的相组成和微观结构, 研究了原位合成SiC对复合材料微观结构、抗弯强度和显微硬度的影响, 分析了复合材料力学性能的变化规律。结果表明: 复合材料的基体相为Al相, 第二相为Si相和SiC相; 原位合成的SiC颗粒弥散细小的分布在Al基体中, 其颗粒尺寸主要分布在0.2~2.8 μm, 具有亚微米、微米级的多尺度特性; 随着SiC质量分数的不断增加, 复合材料的显微硬度增大, 同时颗粒的平均尺寸仅由0.81 μm增大到1.13 μm, 但仍均匀分布, 正是这种尺寸稳定性, 使得SiC/Al-18Si复合材料硬度远大于Al-18Si; 当SiC质量分数为30%时, 材料的显微硬度最高, 达到HV 134, 相较于Al-18Si提高了88%。     

高硅铝合金及颗粒增强铝基复合材料组织性能的探究

采用真空热压烧结工艺制备Al-30Si合金、30%Sip/Al、30%SiCp/2024Al、30%SiCp/6061Al(均为体积分数)复合材料,测定其热膨胀系数及力学性能。利用扫描电镜(SEM)、能谱仪(EDS)对其微观组织结构及断口形貌进行表征,探究了高硅铝合金及颗粒增强铝基复合材料的组织与性能,分析了材料的断裂机制。结果表明:SiCp/2024Al复合材料中SiC颗粒分布均匀,组织致密,综合性能好,热膨胀系数(CTE)为13.69×10-6/K,硬度达到134 HB,极限抗拉强度达353 MPa。SiCp/6061Al复合材料中SiC颗粒分布较均匀,界面结合较好,组织不够致密,有少许孔隙,性能较好。SiCp/6061Al和SiCp/2024Al复合材料的断裂方式都是界面基体的撕裂结合SiC颗粒的断裂。Sip/Al复合材料中Si颗粒分布较均匀,断裂方式为界面脱开,性能较差。Al-30Si合金在烧结过程中形成大量板条状的Si相,性能最差,断裂方式以合金撕裂为主。     

工艺参数对Fe3Al/Al2O3复合材料力学性能的影响研究

以自制的亚微米Fe3Al为增强相、Al2O3为基体相,通过常压烧结制备出Fe3Al/Al2O3复合材料,研究了Fe3Al含量、烧结温度及保温时间对复合材料力学性能的影响.结果表明:增加Fe3Al含量、提高烧结温度及延长保温时间都可以不同程度的提高复合材料力学性能.最佳工艺参数为:Fe3Al含量(质量分数)为15%,成形压力为2488MPa,烧结温度为1380℃.此条件下制备的复合材料的各项力学性能较好:相对密度为93%,维氏硬度为9.3GPa,断裂韧度为7.51MPa·m1/2.烧结温度对提高复合材料力学性能的影响较大.     

粉末冶金制备SiC/6061Al复合材料的显微组织和力学性能研究

采用粉末冶金法制备了体积分数为35%的SiC_p/6061Al基复合材料,研究了复合材料的显微组织和基体与增强体颗粒界面对复合材料力学性能的影响。结果表明:SiC颗粒在基体中分布均匀,基体与增强体之间的界面结合情况较好,复合材料致密度高,抗拉强度较高。     

烧结温度对Al_3Ni金属间化合物增强铝基复合材料力学性能的影响

通过粉末冶金原位合成法制备Al3Ni金属间化合物增强铝基复合材料。采用X射线衍射,扫描电镜,硬度测试和压缩强度测试,研究烧结温度对复合材料微观结构和力学性能的影响。结果表明:在铝基体中成功获得了均匀分布的金属间化合物Al3Ni增强相;随烧结温度从570℃上升到590℃,复合材料的密度从2.435 g/cm-3上升到2.990 g/cm-3,维氏硬度从~24升高到~37;经590℃烧结制备的复合材料表现出了高的压缩强度(255 MPa)和伸长率(~40%)。     

双尺度SiC颗粒增强铝基复合材料制备工艺研究

通过粉末冶金真空热压烧结法制备双尺度(纳米、微米)混杂SiC颗粒增强铝基复合材料,研究不同烧结温度和压力对复合材料的组织、密度、硬度及耐磨性的影响。试验结果表明:SiC颗粒在复合材料基体中分布均匀,基体与增强体界面结合较好。随着烧结温度和压力的增高,复合材料的致密度、硬度、耐磨性均先增大后减小,最佳烧结温度和压力分别为460℃和30 MPa,微纳米混杂颗粒增强、单一微米颗粒增强、单一纳米颗粒增强复合材料的硬度分别是76.6 HV、70.7 HV、62.75 HV,比基体分别提高52.4%、40.6%、24.8%,耐磨性分别是基体的2.22倍、1.71倍、1.42倍。     

不同陶瓷颗粒增强铁基复合材料力学性能的研究(英文)

Mechanical properties of iron matrix composites reinforced by different types of ceramic particles(SiC,Cr3C2,TiC and Ti(C,N)) prepared by the two-stage resistance sintering were studied experimentally.It was found that tensile strength of SiC/Fe composite shows the highest among the four types of composites.The elongation of all the composites decreases as increasing of reinforcement volume fraction.The stress-strain curves of the composites were simulated by Eshelby approach modeling to reveal the strengthening mechanisms.The modeling and microstructure observations suggest that the strengthening mechanism of the iron matrix composites relies not only on load sharing of the reinforcements but also on reinforcement increasing matrix strength.     

陶瓷颗粒增强粉末冶金Fe-2Cu-0.6C复合材料的微观结构和力学性能

采用传统粉末冶金压制/烧结技术，经600 MPa压制、1140℃烧结制备了陶瓷颗粒增强（SiC、TiC及TiB₂陶瓷颗粒，质量分数0~1.6%）Fe-2Cu-0.6C低合金钢复合材料，对三种复合材料的微观结构和力学性能进行了研究。结果表明:在烧结过程中，SiC与TiB₂颗粒与基体发生反应，故而与基体界面结合良好；当添加质量分数为1.6%的SiC颗粒时，复合材料烧结后的布氏硬度与抗拉强度分别比基体提高了35.9%、69.4%；添加质量分数为1.2%的TiB₂颗粒时，复合材料相对密度比基体提高了5.3%，其烧结硬度、抗拉强度与基体相比分别提高了77.9%、72.6%；由于烧结过程中TiC颗粒不与基体发生反应，故而添加TiC颗粒对复合材料的布氏硬度、抗拉强度影响不大。     

混料时间和挤压对SiC增强纯Al基复合材料显微组织和力学性能的影响

采用粉末冶金法制备SiC颗粒增强工业纯Al基复合材料,研究混料时间和挤压对复合材料显微组织和力学性能的影响。研究表明:机械混粉过程存在最佳的混料时间,混料时间为16 h时SiC颗粒分布均匀,复合材料的密度高、力学性能好。挤压可以改善复合材料的界面结合强度、减少孔洞的数量,从而提高材料的致密度和力学性能。烧结态复合材料的断裂机制以基体的脆性断裂以及增强相与基体的界面脱粘为主。挤压态复合材料的断裂以基体的韧性断裂以及SiC颗粒的脆性断裂为主,伴随着少量的基体与SiC颗粒的界面脱粘。     

12%SiCp/Al复合材料制备工艺及力学性能研究

对碳化硅颗粒进行表面氧化酸洗处理，采用粉末冶金加热挤压工艺制备了12％SiCp／Al（体积分数）复合材料。利用金相显微镜和电镜对微观组织进行了观测，拉伸试验测试复合材料的力学性能。试验结果表明：SiC颗粒在铝基体中分布比较均匀；T6热处理条件下12％SiCp／Al复合材料的屈服强度和抗拉强度分别约为472．4MPa、525．7MPa，伸长率为6．5％，弹性模量为92．7GPa。     

Effect of reinforcement-particle-orientation anisotropy on the tensile and fatigue behavior of metal-matrix composites

The effect of extrusion-induced particle-orientation anisotropy on the mechanical behavior of metal-matrix composites (MMCs) was examined. In this study, we have shown that this anisotropy has a significant influence on the tensile and fatigue behavior SiC particle-reinforced Al alloy composites. The preferred orientation of SiC particles was observed parallel to the extrusion axis, with the extent of orientation being highest for the lowest-volume-fraction composites. The composites exhibited higher Young’s modulus and tensile strength along the longitudinal direction (parallel to the extrusion axis) than in the transverse direction. The extent of anisotropic behavior increased with increasing volume fraction, because of the increasing influence of the SiC reinforcement on the Young’s modulus and tensile properties. The preferred orientation also resulted in anisotropy in the fatigue behavior of the composite material. The trends mirrored those observed in tension, with higher overall fatigue strengths for both orientations and a higher anisotropy with increasing volume fraction of particles. The influence of particle-orientation anisotropy and the resulting tensile and fatigue damage mechanisms is discussed.     

SiC晶须含量对镁基复合材料性能影响的研究

采用加压烧结法制备镁基复合材料,研究不同含量的SiC晶须对镁基复合材料密度、硬度、抗拉强度、抗压强度、摩擦磨损等性能的影响。结果表明:镁基复合材料的致密度并不随SiC晶须质量分数的改变而发生规律性变化;材料的硬度随着晶须质量分数的增加而增大;与基体材料ZK60相比,添加SiC晶须的镁基复合材料的抗拉强度、抗压强度、弹性模量、压缩模量和伸长率都有一定提高,当SiC晶须的质量分数为20.0%时,复合材料烧结体的常温力学性能最好;通过对烧结材料磨损量变化的分析,发现当SiC晶须质量分数为10.0%时,摩擦磨损性能最好。综合比较分析,SiC晶须的质量分数为15.0%时,增韧增强效果最佳。     

Study of Tribological and Mechanical Properties of A356–Nano SiC Composites

In the present investigation, the microstructural, wear, tensile and compressive properties of Al?C7Si alloy matrix nano composites have been discussed. It is noted that the composites contain higher porosity level in comparison to the matrix and increasing amount of porosity is observed with the increasing volume fraction of the reinforcement phase in the matrix. The wear sliding test disclosed that the wear resistance of the nano SiC reinforced composites is higher than that of the unreinforced alloy. It is believed that the presence of SiC particles could shield the matrix and silicon phase from directly experiencing the applied load from the counterface. It was revealed that the presence of nano-SiC reinforcement also enhanced the hardness, tensile and compressive yield strength of Al?C7Si alloy which can be attributed to small particle size and good distribution of the SiC particles and grain refinement of the matrix. The highest yield strength and UTS was obtained by the composite with 3.5?vol% SiC nano-particles. The results show that the addition of nano-particles reduces the elongation of A356 alloy.     

Physical Properties of SiCp/Sialon Composites with 4% Y2O3

SiCp/Sialon ceramic manix composites were fabricated by pressureless sintering method using the Sialon powder synthesized from the kaolin clay and submicron SiC particles. The best sintering parameter of SiCp/Sialon composites with 4% (mass fraction) Y2O3 is 1500 ℃×2 h. It is shown that with the increasing of SiCp content, the bulk density decreases, the apparent porosity increases, the flexure strength increases at first and then decreases, the fracture toughness increases and hardness gradually decreases. The best physical properties can be obtained with 10 mass% SiCp, and the bulk density is 3.06 g ·cm-3, apparent porosity is 2.4％, flexure strength is 389.5 MPa, and Vickers hardness is 18.4 GPa. There will be 1280 MPa radial tensile stress and 640 MPa tangential stress in side of Sialon of interphase boundary between SiCp and Sialon phase by calcilation. The mechanism of improvement of SiC content on mechanical properties are also discussed.     

Effect of Graphite and SiC Addition into Cu and SiC Particle Size Effect on Fabrication of Cu–Graphite–SiC MMC by Powder Metallurgy

Here we have reported individual and combined effect of graphite and SiC into Cu matrix during fabrication of Cu–graphite–SiC hybrid metal matrix composite by powder metallurgy. Mechanical properties of the composites are enhanced by simultaneous addition of 1, 3, 5, 10 and 15 vol. % of graphite along with 2, 5 and 10 wt. % of SiC into pure Cu, whereas electrical conductivity deteriorates. Composites are fabricated by cold compaction of composite powder mixture followed by conventional sintering in a tubular furnace at 900 °C for 1 h in argon atmosphere. For comparison, SiC powder size of 5 and 50 µm are used to study the effect of SiC particle size on microstructure, mechanical and electrical properties of the composites. Optical microscopy and scanning electron microscopy reveal the homogeneous distribution of graphite and SiC in matrix and good compatibility between Cu–graphite and Cu–SiC particles. Hardness of the composites decreases with increase in graphite and increases with increase in SiC content. Composites containing fine SiC particles show higher hardness value as compared to coarse particles. Maximum Vickers hardness value of 75 is obtained for Cu-1 vol. % graphite-10 wt. % SiC composite. Electrical conductivity decreases with increase in both graphite and SiC content. Composites containing coarse SiC particles exhibit higher electrical conductivity than fine SiC.     

液态反应合成Mg-Li-MgO/Mg_2Si复合材料的组织与性能

用ＤＴＡ对ＳｉＯ２ 与ＭｇＬｉ 合金反应合成复合材料的热力学进行了研究, 证明反应能够进行。检测结果表明反应生成的粒子尺寸细小且分布均匀。复合材料的强度、硬度、弹性模量明显提高; 该复合材料的延伸率低于基体合金, 但仍可达到较高水平（ ＞ ４％） , 高于Ａｌ２Ｏ３ 及ＳｉＣ纤维增强复合材料。