自生TiCp/2024复合材料熔体挤压组织与力学性能

对自生ＴｉＣｐ／２０２４复合材料采用Ｔ４和Ｔ６两种热处理制度,测试了该材料的σｂ、σｓ、Ｅ和δ。通过ＳＥＭ观察和分析了熔体挤压ＴｉＣｐ／２０２４复合材料的显微组织和断口形貌。结果表明：在Ｔ６状态下ＴｉＣｐ含量为１５ｗｔ％的复合材料的σｂ、σｓ、Ｅ分别达到５４０ＭＰａ、４３０ＭＰａ、９２ＧＰａ,δ为３．２％,断裂形式为韧性断裂,由此可以认为自生ＴｉＣｐ／２０２４复合材料具有优良的综合力学性能。     

原位复合TiCP/LD7复合材料的组织与力学性能

采用原位复合工艺制备了自生TiCp/LD7复合材料坯料,经济热压成φ12的棒材,并进行了T6热处理,通过SEM观察和分析了热挤压TiCp/LD7复合材料的显微组织和断口形貌,测试了材料的σb,σs,E和δ0结果表明,TiC颗粒含量为20wt%,TiCp/LD7复合材料σb,σs,E,分别为417MPa,373MPa,92GPa,δ为4．5％,断裂形式为韧性断裂。     

Effect of Thermal Cycling Treatment on Microstructure and Mechanical Properties of AlNp/2024Al Composite

The AlNp/2024 composite with a high volume fraction (50%) was fabricated by squeeze casting. Its mechanical properties were investigated by tensile tests at ambient temperature and the microstructure was observed by a transmission electron microscope (TEM). It was indicated that after six thermal cooling cycles treatment the AIN/2024Al composite exhibited higher elastic limit (σ0.01), tensile strength (UTS) and elastic modulus (E). TEM observation showed that there was higher dislocation density both in the matrix and the particle. δ′ phase is the mainly precipitate.     

原位形成Al3Ti颗粒对SiCp／2024Al复合材料性能及微观结构的影响

本文采用粉末冶金法制制备了含Ｔｉ的ＳｉＣｐ／２０２４Ａｌ复合材料。研究表明，在复合材料制备工艺条件下，部分Ｔｉ与Ａｌ反应形成了Ａｌ３Ｔｉ，粗大的Ａｌ３Ｔｉ／Ｔｉ复合颗粒的存在降低了复合材料的室温拉伸强度和塑性，但可以提高屈服强度和弹性模量。     

Effect of Thermal Cycling Treatment on Microstructure and Mechanical Properties of AlNp/2024A1 Composite

The A1NP/2024 composite with a high volume fraction (50%) was fabricated by squeeze casting. Its mechanical properties were investigated by tensile tests at ambient temperature and the microstructure was observed by a transmission electron microscope (TEM). It was indicated that after six thermal cooling cycles treatment the AIN/2024Al composite exhibited higher elastic limit (ac.ol), tensile strength (UTS) and elastic modulus (E). TEM observation showed that there was higher dislocation density both in the matrix and the particle. Δ’ phase is the mainly precipitate     

铝含量对自生TiCp/2024复合材料的影响

用真空热爆－加压工艺制备了高颗粒含量了ＴｉＣｐ／２０２４复合材料,通过通过采集了记录了不同铝含量时热爆反应的时间－温度曲线,通过ＸＲＤ分析了ＴｉＣｐ／２０２４复合材料的相组成,用扫描电镜分析了ＴｉＣｐ的分布和形貌,结果表明,随着Ａｌ含量的增加,起始反应时间延长,最高反应温度和反应速度降低,当Ａｌ含量小于６５ｗｔ％时反应生成ＴｉＣｐ,当Ａｌ含量大于６５ｗｔ％时除了反应生成ＴｉＣｐ外,还存在的ＴｉＡｌ     

Microstructure and Mechanical Properties of 45 vol.%SiC_p/7075Al Composite

Microstructure and mechanical behavior of high volume content Si Cp/7xxx Al composites have not been explored yet. Therefore, in the present work, 45 vol.% SiC p/7075 Al composite has been prepared by pressure infiltration method. High density dislocations were found around Si C/Al interface in SiC p/7075 Al composite after water-quenching and aging treatment. Fine dispersed nano-η′ phases were observed after the aging treatment. Adverse to other Si Cp/Al composites prepared by the pressure infiltration method,an interface layer was observed between SiC particles and Al matrix. Furthermore, high-resolution transmission electron microscopy(HRTEM) observation indicated that this interface layer was coherent/semicoherent with that of the SiC particles. 45 vol.% SiC p/7075 Al composite demonstrated high tensile strength(630 MPa) and micro-ductility. Compared to aged Si Cp/2024 Al composite, the aged Si Cp/7075 Al composite showed an increase of about 200% in the tensile strain and 90% in the tensile strength, respectively.It is speculated that nano-η′ phases in the Al matrix significantly contributed to the strengthening effect while the interface layer between Si C and Al matrix might be beneficial to the strength and plasticity of Si Cp/7075 Al composite.     

Microstructure and Mechanical Property of in-situ Al-Cu/TiC Composites

An approach named direct reaction synthesis (DRS) has been developed to fabricate particulate composites with an extremely fine reinforcement size. ID situ Al matrix composites were fabri-cated by DRS. Extensive analysis of the composites microstructure using SEM and TEM identify that the reinforcement formed during the DRS process is Ti carbide (TiC) particle, generally less than 1.0 μm. The reacted, semisolid extruded samples exhibit a homogeneous distribution of fine TiC particles in Al-Cu matrix, Mechanical property evaluation of the composites has revealed a very high tensile strength relative to the matrix alloy. Fractographic analysis indicates ductile failure although the ductility and strength are limited by the presence of coarse titanium aluminides (Al3Ti).     

低频电磁场对n-SiCp/2024复合材料组织与性能的影响

分别采用低频电磁铸造(LFEC)与传统半连续铸造(DC)制备n-SiC_p/2024复合材料铸锭,并对铸锭进行挤压以及T6热处理。通过金相组织观察(OM)、TEM、室温力学性能测试等手段,分别研究了低频电磁铸造与传统半连续铸造工艺对n-SiC_p/2024复合材料的微观组织、力学性能的影响情况。实验结果表明:DC制备的n-SiC_p/2024复合材料铸锭表面局部存在偏析瘤,大多数n-SiC_p团聚在晶界处,只有少数聚集在晶粒内部;LFEC制备的n-SiC_p/2024复合材料铸锭组织晶界清晰,n-SiC_p团聚现象基本消失,组织均匀,晶粒细化效果明显。LFEC制备工艺可以有效细化n-SiC_p/2024复合材料铸锭的晶粒尺寸,其电磁搅拌作用对消除n-SiC_p颗粒的团聚现象有显著作用;与DC工艺相比,LFEC可同时提高复合材料的强度与延伸率。     

超音速激光沉积增材制造CNTs/Cu复合材料微观结构及力学性能研究

目的 研究超音速激光沉积增材制造CNTs/Cu复合材料的微观结构及力学性能。方法 对CNTs进行表面镀铜处理,提高它与Cu黏接相之间的润湿性,增强CNTs/Cu之间的界面结合,利用超音速激光沉积技术(Supersonic Laser Deposition,SLD)增材制备不同CNTs含量的CNTs/Cu复合材料,对比研究了CNTs含量和退火温度对CNTs/Cu复合材料微观结构及力学性能的影响规律,并采用能谱仪对拉伸断口微区进行元素分析测定。结果 SLD制备的CNTs/Cu复合材料具有优异的塑性变形能力,而强度较高的CNTs通过嵌入铜粉颗粒之间的缝隙提升了沉积质量。对复合材料微观组织进行表征发现组织无明显孔隙、致密性良好,且无烧蚀现象。CNTs的加入有效提高了CNTs/Cu复合材料的抗拉性能,并且随着CNTs含量的上升,CNTs/Cu复合材料的极限抗拉强度(Ultimate Tensile Strength,UTS)稳步上升;当CNTs质量分数为0.3%时,CNTs/Cu复合材料的UTS为36.33 MPa,是CNTs质量分数为0.05%时的1.35倍。随着退火温度的升高,CNTs/Cu复合材料的UTS表现为先增大后减小的趋势,在500 ℃时UTS达到最大值。结论 由于激光加热软化的效果与表面镀铜的包覆作用,CNTs能够均匀地分布在CNTs/Cu复合材料内部,同时明显增强复合材料内部颗粒的界面结合强度,后续的热处理有助于使材料从不稳定的机械结合逐步转换为冶金结合,显著提高复合材料的抗拉性能。     

TiCP/Ti-6Al-4Sn-2Mo-0.2Si复合材料的组织与机械性能

用熔铸法制备了体积分数分别为8%和12％TiC的TiCp/Ti-6Al-4Sn-2Mo-0.2Si复合材料，通过SEM、TEM、XRD等手段研究复合材料的微观组织和断口形貌。TiC颗粒的加入使复合材料的铸态强度比基体有了大幅度的提高，但同时出现了含低体积分数增强相材料的强度和延伸率均比高体积分数材料高的现象，其原因主要来自于铸态下TiC形态的差异，后者组织中存在较多的枝晶状TiC，而前者组织中绝大多数TiC为细小颗圆整颗粒，有利于合金性能的提高。因此自生复合材料中增强相形态对性能影响，有时比体积分数更重要。     

成型压力对5428VB/T700复合材料微观结构与性能的影响

5428VB/TT00预浸料适于真空成型高性能复合材料.为了进一步提高该类材料的通用性,本工作采用热压罐法成型5428VB/TT00复合材料,研究了加压时机、施加压力大小等对复合材料基本力学性能的影响,采用超声扫描、微观结构分析等对复合材料板材质量进行了分析,并和相应的真空成型5428VB/T700复合材料进行了比较.结果表明,在130℃/1h前施加0.3～0.6MPa的压力,5428VB/T700复合材料的短梁剪切强度相对于真空压力成型体系有较明显降低,但随压力的增大有增加趋势;在130℃/1.5～2.0h施加0.3～0.6MPa压力时,5428VB/T700复合材料的基本力学性能相对于130℃/1h前施加压力的体系有较明显提高,并随压力的增大有增加趋势,当施加的压力达到0.6MPa以上时,复合材料的基本力学性能和质量优于相应的真空压力成型复合材料体系.分析了复合材料成型过程中的气泡运动历程以及孔隙的形成原因等.     

Microstructure and Wear Resistance of In situ TiCp Composite Coating by Laser Cladding

1.IlltroductionThesimpleandeconomicalwaytorealizeamul-tiphasemicrostructurecontainingthetoughmatrixwithafinelydispersedinerthardphase,whichmeetstherequirementforhighwearresistanceatroomandespeciallyelevatedtemperatures,isofgreatimpor-tanceinmaterialscience.Ceramicparticulate-incorporationtoprovideametalmatrixcomposites(MMCs)layeronvarioussubstratesbylasercladdingisarelativelynewlyde-velopedtechnique,inwhichthepowdersofanal-loywithadesirablecompositionandathinsur-facelayerofthesubstratemateria…     

搅拌铸造SiCp/2024复合材料热挤压-轧制变形组织及性能

利用搅拌铸造-热挤压-轧制工艺制备SiCp/2024复合材料薄板.通过金相观察(OM)、扫描电镜(SEM)及力学测试等手段研究了该复合材料在铸态、热挤压态及轧制态下的显微组织及力学性能,分析了材料在塑性变形过程中显微组织及力学性能的演变.结果表明,该复合材料铸坯主要由80～100μm的等轴晶组成,粗大的晶界第二相呈非连续状分布,SiC颗粒较均匀地分布于合金基体中;热挤压变形后,晶粒沿挤压方向被拉长,SiC颗粒及破碎的第二相呈流线分布特征;轧制变形后,基体合金组织进一步细化,晶粒尺寸为30～40μm,SiC颗粒破碎明显,颗粒分布趋于均匀,轧制变形对挤压过程中形成的SiC颗粒层带状不均匀组织有显著     

Microstructure and Thermal Properties of Aluminum/Graphene Composite

正Aluminum matrix composites reinforced with different content of graphene nanoplatelets(GNPs)were prepared via ball-milling and microwave sintering process.The contents of graphene nanoplatelets(GNPs)were varied from0.52.0vol.%in aluminum matrix.The impacts of graphene content on microstructure,mechanical performance,electrical and thermal properties     

SiCw／Al－Ni复合材料的组织结构和拉伸性能

研究了挤压铸造法制备的ＳｉＣｗ／Ａｌ－Ｎｉ复合材料的组织结构和拉伸性能．研究结果指出。该种复合材料的显微组织由ＳｉＣ晶须、颗粒状的金属间化合物Ａｌ３Ｎｉ及α－Ａｌ组成。金属间化合物Ａｌ３Ｎｉ对位错运动有明显的钉扎作用。ＳｉＣｗ／Ａｌ－Ｎｉ复合材料具有较好的常温拉伸性能和优异的高温拉伸性能。     

Fabrication,Microstructure and Mechanical Properties of TiC/Ti_2AlC/TiAl_3 in situ Composite

This paper described a process for synthesizing a new multiphase TiC/Ti2AlC/TiAl3 composite,in which Ti,Al4C3 and graphite powders were utilized as raw materials,and in situ spark plasma sintering-reactive sintering(SPS-RS) methods were involved.The intermediate phases of Ti3Al and TiAl were found during the reactive sintering process and the reactions for the phase’s formation were proposed.The microstructure and mechanical properties of the composites were investigated.The high-resolution transmission electron microscopy(HRTEM) image of the interface showed that no amorphous phases were detected along the grain boundary.The orientation relationships between the Ti2AlC and the TiC were shown to be(0001)Ti2AlC||(111)TiC and [110]Ti2AlC||[110]TiC.The average hardness,fracture toughness,Young’s modulus and bending strength of the composite were 15.1±0.8 GPa,4.9±0.3 MPa·m 1/2,261±13 GPa and 776±18 MPa,respectively.The toughening mechanism was also discussed.     

C/C-ZrC复合材料的微观结构和力学性能研究

采用ZrOCl₂溶液浸渍法把锆化合物引入碳纤维预制体, 经热处理、热梯度化学气相渗透致密化和高温石墨化工艺制备了C/C-ZrC复合材料。性能测试结果表明, C/C复合材料的弯曲强度和模量随ZrC含量的增加而增大, ZrC含量为12.08wt%时, 其强度和模量分别为42.5 MPa 和9.6 GPa, 比未改性试样分别提高了70.0%和43.3%。基体中结合较弱的微米级ZrC颗粒的存在不利于碳基体强度的提高, 但其对材料最终性能的影响是次要的, 碳基体中亚微米/纳米级ZrC颗粒的存在和良好的ZrC-C界面结合, 提高了碳基体的强度和模量, 进而提高了复合材料的最终性能。