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.     

搅拌铸造SiC_p/2024铝基复合材料的显微组织与力学性能

利用搅拌铸造?热挤压工艺制备SiCp/2024铝基复合材料板材,研究该复合材料铸态、热挤压态和热处理态的显微组织及力学性能。结果表明:SiC颗粒较均匀地分布于铸锭中,大部分SiC颗粒沿晶界分布,少数颗粒分布于晶内,晶界粗大的第二相呈非连续状分布;复合材料经热挤压变形后,显微孔洞等铸造缺陷明显消除,破碎的晶界第二相及SiC颗粒沿热挤压方向呈流线分布,复合材料的强度和塑性显著提高;对热挤压板材进行(495℃,1h)固溶处理+(177℃,8h)时效处理后,其抗拉强度达430MPa,此时的主要析出强化相为S′(Al2CuMg);热挤压变形有利于改善SiC颗粒与基体合金的界面结合,热处理SiCp/2024铝基复合材料的主要断裂方式为基体合金的延性断裂、SiC颗粒断裂和SiC/Al的界面脱粘。     

旋转摩擦挤压制备石墨烯增强铝基复合材料的微观结构与力学性能

本文将石墨填入纯铝1060板材中,试图通过旋转摩擦挤压(RFE)的方法实现石墨的原位剥离而制备石墨烯增强铝基复合材料,研究了石墨与基体组织的演变、复合材料的界面结构与力学性能。结果表明,石墨在RFE大塑性变形作用下分散于基体的同时,被破碎并原位剥离出大量5~12层的石墨烯,添加石墨使基体晶粒得到明显细化、大角度晶界增加；石墨破碎产生大量的边缘缺陷有利于原子的扩散,结果在石墨烯和基体间易形成扩散界面,比机械结合界面更有利于载荷的传递；添加石墨使材料的力学强度明显提高,特别当石墨添加量0.82wt%时,复合材料的屈服强度和抗拉强度达到76.4MPa和163.2MPa,较同等条件RFE的基体分别提高了91%和71.4%,取得了较好的增强效果,此时复合材料的延伸率虽比基体有所下降但也达到25.3%,有较好的强塑性配合。     

SiC_p/2024铝合金复合材料粉末混合半固态挤压法制备

研究了SiCp/ 2 0 2 4铝合金复合材料的粉末混合 半固态挤压成形工艺及所制备材料的组织和界面特征。不同温度下半固态挤压的挤压力与位移曲线表明 ,半固态挤压过程的成形力低且稳定。SEM和TEM电镜观察结果表明 ,该工艺可以获得增强颗粒分布均匀、基体组织致密、界面结合良好且无界面反应的复合材料型材。分析了半固态挤压后复合材料的力学性能 ,结果表明 :与基体合金相比 ,复合材料的弹性模量、屈服强度、抗拉强度均有很大提高 ;与其它工艺生产的该复合材料相比 ,所制备的复合材料的塑性相对较高。     

Semi-solid extrusion of TiCp/2024Al composites prepared by co ntact reaction method

1　ＩＮＴＲＯＤＵＣＴＩＯＮＢｅｃａｕｓｅｏｆｔｈｅｉｒｈｉｇｈｓｐｅｃｉｆｉｃｓｔｒｅｎｇｔｈｓ,ｓｐｅｃｉｆｉｃｍｏｄｕｌｉ,ｗｅａｒｒｅｓｉｓｔａｎｃｅａｎｄｔｈｅｒｍａｌｓｔａｂｉｌｉｔｙ,ｔｈｅＡｌｂａｓｅｄｃｏｍｐｏｓｉｔｅｓｒｅｉｎｆｏｒｃｅｄｂｙｃｅｒａｍｉｃｐａｒｔｉｃｌｅｓｈａｖｅａｔｔｒａｃｔｅｄｍｕｃｈｉｎｔｅｒｅｓｔｉｎｔｈｅｄｅｖｅｌｏｐｍｅｎｔｏｆｍａｎｕｆａｃｔｕｒｉｎｇｐｒｏｃｅｓｓｅｓｆｏｒｓｕｃｈｃｏｍｐｏｓｉｔｅｓ.Ｔｈｅｆａｂｒｉｃａｔｉｏｎｐｒｏｃｅｓｓｅ…     

喷射共沉积SiC_p/2024复合材料的显微组织与力学性能

利用喷射共沉积-热挤压-轧制工艺制备SiC_p/2024复合材料板材.研究该复合材料轧板热处理后的显微组织及力学性能,并确定其最佳的热处理工艺条件.结果表明:轧制态复合材料组织细小均匀,晶粒尺寸为3～4 μm,SiC颗粒均匀分布在基体合金中;采用490 ℃、1 h固溶处理和170 ℃、8 h时效后,SiC_p/2024复合材料轧板的抗拉强度、屈服强度和伸长率分别为480 MPa、358 MPa和6.4%,基体合金中存在大量细小的第二相颗粒,为Al_2MgCu及Al_2Cu相;峰时效状态时复合材料的布氏硬度值为228 HB,与轧板原始硬度相比较增幅达130%;喷射共沉积SiC_p/2024复合材料轧板到达峰时效时间比铸造2024铝合金的短,这主要是因为喷射沉积基体合金内细小均匀的晶粒组织、基体合金内高密度的位错组态以及SiC颗粒的引入,均有利于沉淀相的提前析出.     

35% SiC_p/2024A1复合材料的热变形行为(英文)

采用Gleeble-1500D热模拟试验机,对35%SiCp/2024A1复合材料在温度350~500°C、应变速率0.01~10s-1的条件下进行热压缩试验,研究该复合材料的热变形行为与热加工特征,建立热变形本构方程和加工图。结果表明,35%SiCp/2024A1复合材料的流变应力随着温度的升高而降低,随着应变速率的增大而升高,说明该复合材料是正应变速率敏感材料,其热压缩变形时的流变应力可采用Zener-Hollomon参数的双曲正弦形式来描述;在本实验条件下平均热变形激活能为225.4 kJ/mol。为了证实其潜在的可加工性,对加工图中的稳定区和失稳区进行标识,并通过微观组织得到验证。综合考虑热加工图和显微组织,得到变形温度500°C、应变速率0.1~1 s-1是复合材料适宜的热变形条件。     

Microstructure and properties of mechanical alloying particles reinforced aluminum matrix composites prepared by semisolid stirring pouring method

Aluminum matrix composites reinforced with mechanical alloying particles(SiC_p) were fabricated by the semisolid stirring pouring method. The inf luence of mechanical alloying particles and Mg on the microstructure and mechanical properties of the composites was investigated by means of optical microscopy(OM), X-ray diffraction scanning(XRD), electron microscopy(SEM) and energy dispersive spectroscopy(EDS). Results show that the addition of Mg converts the agglomerate mechanical al oying particles in ZL101 matrix composites into dispersed distribution in ZL101-Mg matrix composites, large matrix grains into f ine equiaxed matrix grains, and eutectic phase into f ine particles. So the mechanical properties of ZL101-Mg matrix composites are better than those of ZL101 matrix composites. The mechanical properties of ZL101/ZL101-Mg matrix composites are gradually increased with the increase of the volume fraction of mechanical alloying particles. When the volume fraction of mechanical alloying particles is 3%, the Vickers hardness and ultimate tensile strength of the ZL101/ZL101-Mg matrix composites reach their maximum values.     

硼酸铝晶须增强铝基复合材料的显微组织、力学性能和磨损性能（英文）

通过传统的粉末冶金技术制备不同含量硼酸铝晶须(ABOw)(5%, 10%, 15%,质量分数)增强的商业纯铝基复合材料,并对其显微组织特征和力学性能进行研究。采用粉末冶金方法有效混合铝粉和ABOw,将混合粉冷压后在600℃下烧结。通过光学显微镜(OM)、扫描电子显微镜(SEM)、能谱分析(EDS)、透射电子显微镜(TEM)和X射线衍射(XRD)对烧结后的复合材料进行显微组织表征,测定复合材料的孔隙率随ABOw含量的变化,研究ABOw含量变化对复合材料的力学性能,包括硬度、抗弯强度和抗压强度的影响,及复合材料在恒定载荷下、不同滑动距离下的干滑动磨损行为。结果表明,当ABOw含量为10%(质量分数)时,复合材料具有最大的抗弯强度和抗压强度,分别为172 MPa和324 MPa,并且硬度得到改善,约为HV 40.2。但是,随着ABOw含量的进一步增加,性能降低。含10%ABOw复合材料的耐磨性能也得到显著提高。Al-10%ABOw复合材料优异的综合性能归因于其具有良好的界面结合性能、低的孔隙率和好的组织均匀性。     

Fabrication and mechanical properties of in situ TiC/Ti metal matrix composites

In situ TiC particle reinforced titanium matrix composites (TMCs) were successfully fabricated by reactive sintering of Ti + Mo₂C and Ti + VC compacts. The results of the tensile tests at ambient and elevated temperatures show that the strength of the composites increases with increasing additive content (Mo₂C and VC), and decreases with increasing temperatures. Comparing the two types of TMCs, the Ti + VC composites have a lower strength than the Ti + Mo₂C composites, but can more effectively retain the strength to elevated temperatures. Microstructural analyses show that the main strengthening mechanisms of the TMCs are solid solution, grain refinement and particulate strengthening. Different dominant strengthening mechanisms in different composites are responsible for the variations of the mechanical properties. At elevated temperatures, the volume fraction of TiC particles is the main factor for increasing the strength.     

Microstructural characterization and mechanical properties of friction surfaced AA2024−Ag composites

The effects of Ag on the microstructure, mechanical properties, and electrical conductivity of AA2024 aluminum alloy coating were investigated. It was fabricated by friction surfacing as an additive manufacturing process. To carry out this investigation, Ag was added by 5.3, 10.6, and 16.0 wt.% to an AA2024 consumable rod by inserting holes in it. It was found that due to the strengthening by solid solution and the formation of precipitates and intermetallic containing Ag, the driving force for grain growth is reduced and consequently the grain size of the coating is decreased. After artificial aging heat treatment, the electrical conductivities of the coatings containing 0 and 16.0 wt.% Ag are increased by 4.15% (IACS) and decreased by 2.15% (IACS), respectively. While considering a linear relationship, it can be proposed that for a 1 wt.% Ag increase, the strength and hardness of the coating will be increased by 1.8% and 1.0%, respectively. It was established that the effect of Al₆(Cu,Ag)Mg₄ precipitate formation on strengthening is greater than that of Ag-rich intermetallic.     

真空热压SiC_p/2024Al复合材料力学性能与显微结构

采用真空热压法制备了体积分数为30%的Si Cp/2024Al复合材料,研究了该复合材料的显微组织结构及力学性能。结果表明,复合材料组织致密,颗粒与基体界面结合状况较好,Si C颗粒在铝基体中基本上分布均匀。经490℃、2 h固溶处理和170℃、8 h人工时效后,Si Cp/2024Al复合材料的抗拉强度、屈服强度和伸长率分别为409 MPa、325 MPa和4.9%,基体中存在大量的纳米析出相为S'(Al2Cu Mg)。随Si C颗粒加入,复合材料力学性能提高,其断裂方式为基体开裂和界面处撕裂。     

石墨烯纳米片增强铝基复合材料的制备与性能

采用高能球磨、放电等离子烧结以及热挤压工艺制备含量为5.0％(体积分数)的石墨烯增强铝基复合材料.分别采用X射线光电子能谱、透射电镜及拉伸试验研究挤压态复合材料的显微组织与力学性能,发现5.0％(体积分数)的石墨烯分散在铝晶界上,并且未与铝基体发生界面反应.最终,挤压态复合材料的屈服强度和抗拉强度高达462 MPa和4...     

Effect of aging treatment on mechanical properties of （SiCw＋SiCp）/2024Al hybrid nanocomposites

1 Introduction Metal matrix composites(MMCs) have received much attention because of their improved specific strength, good wear resistance and higher thermal conductivity [1?3]. Up to now, most investigators have studied the fabrication process and mecha…     

Processing,characterization, room temperature mechanical properties and fracture behavior of hot extruded multi-scale B4C reinforced 5083 aluminum alloy based composites

Microstructural characteristics and mechanical behavior of hot extruded Al5083/B₄C nanocomposites were studied. Al5083 and Al5083/B₄C powders were milled for 50 h under argon atmosphere in attrition mill with rotational speed of 400 r/min. For increasing the elongation, milled powders were mixed with 30% and 50% unmilled aluminum powder (mass fraction) with mean particle size of >100 μm and <100 μm and then consolidated by hot pressing and hot extrusion with 9:1 extrusion ratio. Hot extruded samples were studied by optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), transmission electron microscopy (TEM), tensile and hardness tests. The results showed that mechanical milling process and presence of B₄C particles increase the yield strength of Al5083 alloy from 130 to 566 MPa but strongly decrease elongation (from 11.3% to 0.49%). Adding <100 μm unmilled particles enhanced the ductility and reduced tensile strength and hardness, but using the >100 μm unmilled particles reduced the tensile strength and ductility at the same time. By increasing the content of unmilled particles failure mechanism changed from brittle to ductile.     

热处理过程中SiCp/2024Al基复合材料的微观组织演变

采用真空热压烧结工艺在580℃下制备了35%(体积分数)SiCp/2024铝基复合材料,利用扫描电镜(SEM)、透射电镜(TEM)、能谱(EDS)、高分辨透射电镜(HRTEM)对复合材料热处理过程中微观组织进行了表征,研究了热压烧结后复合材料的析出相的微观结构以及析出相在热处理过程的演变规律。结果表明,热压烧结后复合材料中存在许多粗大析出相颗粒,包括Al4Cu9,Al2Cu,Al18Mg3Mn2,Al5Cu6Mg2和Al7Cu2Fe。随着固溶温度的提高,粗大析出相颗粒逐渐回溶到Al基体中,当固溶温度达到510℃时,粗大析出相颗粒几乎全部回溶到基体中,但还存在少量的难溶相。复合材料经510℃固溶2 h+190℃时效9 h后,除了少量的难溶相,许多圆盘状纳米析出相Al2Cu和棒针状纳米析出相Al2Cu Mg弥散分布于基体中且与基体的界面为错配度较小的半共格界面,圆盘状纳米析出相的直径为50~200 nm,棒针状纳米析出相长度为100~150 nm。     

铝与氮化硼的反应机理及其复合材料的组织和性能

采用粉末冶金法,通过六方氮化硼纳米片(BNNSs)与Al的原位反应制备多元混杂增强铝基复合材料,研究了BNNSs与Al的原位反应机理以及反应前后对复合材料的相组成、微观组织、界面结构和力学性能的影响.结果 表明:BNNSs与Al混合粉末在630℃放电等离子烧结致密化后,BNNSs与Al并未发生反应.基于此,将烧结坯体在...     

烧结工艺及热挤压对纳米Al2O3p/7075铝基构型复合材料组织与性能的影响

采用粉末冶金与热挤压工艺制备了 10 wt%纳米Al₂O_3p/7075铝基构型复合材料。研究了真空与非真空下不同烧结温度、不同挤压比对复合材料微观组织、致密度、弹性模量、硬度和压缩强度的影响。结果表明：随烧结温度升高,挤压比4:1与8:1构型复合材料的硬度皆为先增加后降低,整体相对基体材料硬度均明显提高;复合材料经过挤压过后材料的致密度均在98 %以上;挤压比4:1,烧结温度为620℃、630 ℃、640℃时,相对于基体复合材料抗压强度分别提高了15.3%,17.2%,14.0%,随温度先增大后降低;挤压比8:1时,相对基体复合材料抗压强度分别提高了33.2%,34.1%,31.1%,强度随温度先增大后降低。而构型复合材料综上实验中弹性模量变化不大。     

2024铝合金超声辅助钎焊接头的微观组织演变及力学性能

对低温下采用Zn-5Al钎料超声辅助钎焊2024铝合金进行研究。在温度为400℃时,采用功率为200W、振幅为15μm、频率为21kHz的超声对试样实施连接。采用超声波来加速Al从母材到焊缝的溶解,从而改变接头的微观组织。同时,通过增加超声时间来降低接头中共晶组织的含量。当超声振动时间从3s增加到30s时,焊缝中共晶相的含量从12.9%减少到0.9%剪切强度提高了20%,并且,当超声振动时间为30s时,接头的剪切强度达到最大为149-153MPa。为了研究接头力学性能的变化,测试了接头中各相的弹性模量和硬度,同时分析了不同超声振动时间下的接头断口形貌。