碳化硅颗粒增强Al基复合材料的新型制备工艺

综述了碳化硅增强铝基复合材料的几种主要制备工艺,重点阐述了高能超声半固态复合法制备SiCp/Al复合材料.首先用渗流法制备SiC体积分数高的SiCp/Al预制块,进行SiC预分散,然后将预制块加入处于半固态温度条件下的铝合金熔体中,最后导入超声波进行搅拌.此法很好地改善了增强颗粒与基体之间的润湿性,使SiC在基体中均匀...     

不同碳化硅和球形石墨含量对混杂增强铝基复合材料力学性能的影响

目的 研究不同增强相配比对SiCp与球形石墨颗粒混杂增强铝基复合材料力学性能的影响.方法 以6092铝合金为基体,采用粉末冶金法制备了球形石墨颗粒(Gr)、SiCp单相增强以及SiCp和Gr混杂增强的铝基复合材料,通过挤压塑性变形与T6强化热处理进一步改善材料的力学性能.结果 所制备的复合材料无孔洞等缺陷,致密度达99...     

热挤压对SiCw·SiCp/2024Al组织与性能的影响

为了研究SiCw·SiCp/2024Al复合材料的热变形行为,对压铸法制备的SiCw·SiCp/2024Al复合材料进行了热挤压变形,并测定了其变形前后的室温拉伸性能.利用扫描电镜和透射电镜对复合材料热变形前后的微观组织进行观察.研究表明:增强体在基体中分布均匀,并与基体有良好的界面结合;热挤压后,纳米颗粒分布的均匀性和分散性得到改善,SiC晶须产生了沿挤压方向的定向排列,且SiC晶须与基体合金的界面结合良好;随着SiC颗粒含量的增加,混杂增强复合材料的抗拉强度随之升高,挤压后复合材料的抗拉强度进一步提高;与基体合金相比,混杂增强复合材料的延伸率下降,热挤压有利于提高混杂复合材料的延伸率.     

SiCp/Al复合材料抗弯性能研究

利用空气气氛下的无压渗透法制备了高体积分数的SiCp/Al复合材料,研究了颗粒粒径、基体合金成分、预处理工艺对复合材料抗弯性能的影响,并采用SEM观测了复合材料抗弯断口形貌.结果表明,SiCp/Al复合材料的抗弯强度随着SiC颗粒粒径减小而增大;基体材料的强度越高,复合材料的抗弯强度越高;复合材料整体上表现出脆性断裂的特征.     

碳化硅颗粒增强7A04铝基复合材料的腐蚀行为

碳化硅颗粒增强7A04(SiCp/7A04)铝基复合材料的应用环境及其腐蚀状况都较复杂.过去,对它的研究方法多样,依据不同,因而其腐蚀结论有异,甚至矛盾.为了研究SiCp/Al复合材料的耐蚀性,用电化学法和失重法研究了SiC颗粒含量和粒度对SiCp/7A04铝基复合材料及基体合金耐腐蚀性能的影响.结果表明,与基体合金相比,SiCp/7A04铝基复合材料耐蚀性下降,SiC含量高的复合材料腐蚀较快,SiC颗粒尺寸越大,复合材料耐蚀性越好;采用扫描电镜(SEM)观察腐蚀后的微观形貌表明,SiC颗粒破坏了基体表面氧化膜的完整性,促进了点蚀的形成,但其自身的稳定性又阻碍了蚀孔的长大.     

碳化硅增强铝基复合材料的力学性能和断裂机制

研究了碳化硅颗粒(SiCp)尺寸对用粉末冶金法制备体积分数为15%的SiCp/2009铝基复合材料力学性能和断裂机制的影响.结果表明,复合材料的强度随着SiCp尺寸的增大而减小,塑性则随着颗粒的增大而增大.当SiCp尺寸为1.5μm时,SiCp/2009A1复合材料的断裂主要以界面处撕裂和基体材料的开裂为主;当SiCp尺寸为20 μm时,复合材料的断裂主要以SiCp断裂为主;当SiCp尺寸处于两者之间时,SiCp/2009A1复合材料界面处撕裂和SiCp断裂的共同作用决定复合材料的断裂.     

P/M—SiCp增强LY12研究

一、引言 空间技术的发展对结构材料的比刚度、比强度以及耐热性提出了越来越高的要求,以复合材料为基础的新型材料应运而生,其中以陶瓷颗粒、晶须、纤维强化的金属基复合材料(MMC)发展尤为迅速。美国通用动力公司采用Al—B复合材料研制成功了A—7飞机起落架后支柱;洛克希德乔治亚分公司采用SiC晶须增强铝基复合材料制造了C—5A军用机油箱;日本丰田汽车也采用MMC制造了ZL—T型发动机活塞。据预测金属复合材料可使军用飞机重量减轻20％～35％。铝及其合金是最有希望的基体材料,例如SiCp增强铝,成本低、耐热性好、比强度高、各向同性。因此具有广泛的发展前景。在成形方法中P/M法较为优越,它解决了Z/M方法中SiCp的分散问题,同时也可精确调整SiCp的含量。在增强剂中颗粒较晶须或纤维更适于工业生产。 二.实验方法 1、粉末的制备及选取 陶瓷增强剂采用纯度为94％,平均粒径为3.5μm的SiCp磨料。选LY12做为基体材料,用超声气体雾化法制粉,冷却速度为10~3℃～10~5℃,粉末经筛分后其形貌见图1,取50～100μmLY12粉与SiCp颗粒一起进行表面处理     

高体分SiC颗粒增强镁基复合材料的显微组织与力学性能EI北大核心

预先对SiC颗粒增强体进行表面氧化处理,然后采用压铸浸渗法制备了体积分数为51.5%的SiCp/Mg-6Al-0.5Mn复合材料。通过压缩性能测试、扫描电镜、透射电镜等方法,研究了复合材料的显微与力学性能。结果表明,在基体Mg-6Al-0.5Mn合金掺入51.5%体积分数的SiC颗粒预制块后,复合材料的组织致密,分布均匀,其断裂方式包括界面脱开、基体韧断和增强体开裂。SiC颗粒与基体之间发生了界面反应,生成了纳米级的Mg2Si化合物。同时,适度的预氧化可以提高基体与颗粒之间的界面结合强度,从而使复合材料抗拉强度得到提高。     

SiCp/MoSi2原位反应高温热压复合工艺的研究

运用乙醇湿法混合和氩气保护原位反应高温热压方法制备了不同配比的SiCp/MoSi2复合材料,研究了原位生成的SiC颗粒对MoSi2基体材料显微结构和室温力学性能的影响.结果表明:原位反应高温热压制备SiCp/MoSi2的工艺是可行的,反应生成的适量SiC颗粒细化了基体晶粒,改善了其力学性能;与该工艺下制备的纯MoSi2相比,含40vol%SiCp的SiCp/MoSi2复合材料室温抗弯强度提高了260%,含50vol%SiCp的SiCp/MoSi2复合材料室温断裂韧性提高了50%;该种工艺的强化机制为细晶强化和弥散强化,韧化机制为细晶韧化.     

固溶时效对Al6092/SiCp/β-LiAlSiO4复合材料力学性能和微观形貌的影响

以6092铝合金（Al6092）为金属基体,碳化硅（SiCp）和β-锂霞石（β-LiAlSiO4）作为陶瓷颗粒增强相,采用粉末锻造工艺制备Al6092/SiCp/β-LiAlSiO4复合材料。探究固溶时效处理对Al6092/SiCp/β-LiAlSiO4复合材料力学性能的影响,揭示固溶时效处理对复合材料微观结构、析出相和位错的强化机制。结果表明,固溶时效处理能提高Al6092/SiCp/β-LiAlSiO4复合材料的刚度和强度,还能促进试样中高位错密度区和Mg2Si析出相的产生,提高复合材料塑性变形所需的应力。此外,微米级SiCp的高模量特性可以自发地承载载荷,β-LiAlSiO4的引入则促进了增强相的分散。总之,固溶时效处理和二元陶瓷颗粒增强相可以共同提高Al6092的抗变形能力。     

Experimental Investigation on Rotary Ultrasonic Face Grinding of SiCp/Al Composites

SiCp/Al composites have been widely used in many fields such as aerospace, automobile, advanced weapon system, etc. But this kind of material, especially with high volume fraction, is difficult to machine due to the reinforced particles existing in matrix, which has limited its further application. Rotary ultrasonic machining (RUM) has many excellent features and it has never been used to machine SiCp/Al composites. In order to improve the machinability and application of SiCp/Al composites, the rotary ultrasonic face grinding experiments of SiCp/Al composites reinforced with 45% volume SiC particles were carried out to investigate cutting force, surface quality, tool wear, and abrasive chip shapes. The experimental results indicate that ultrasonic vibration could reduce cutting force, surface roughness, surface defects, and increase plastic removal ratio. The cutting force could be lowered by an average of 13.86% and the surface roughness could be lowered by an average of 11.53%. The examined results of tool wear patterns suggest that tool wear is mainly caused by grain breakage and grain fall-off. Grinding wheel blockage and grinding burn were not observed in machining process.     

TiB2／Al自润滑复合材料在动压马达零件上的应用研究

复合材料组织致密，颗粒分布均匀．与基体结合紧密．具有较高的弹性模量和抗弯强度。室温下与GCr15轴承钢对磨时其摩擦系数在0．2左右．自磨时摩擦系数在0．08左右．摩擦表面没有明显的粘着或犁削痕连．磨损率明显低于SiCr／Al复合材料和GT35合金．呈现出较好的自润滑性能。     

Effect of submicron size SiC particles on microstructure and mechanical properties of AZ31B magnesium matrix composites

The magnesium matrix composites reinforced with three volume fractions (3, 5 and 10 vol.%) of submicron-SiC particles (∼0.5 μm) were fabricated by semisolid stirring assisted ultrasonic vibration method. With increasing the volume fraction of the submicron SiC particles (SiCp), the grain size of matrix in the SiCp/AZ31B composites was gradually decreased. Most of the submicron SiC particles exhibited homogeneous distribution in the SiCp/AZ31B composites. The ultimate tensile strength and yield strength of the 10 vol.% SiCp/AZ31B composites were simultaneously improved. The study of interface between the submicron SiCp and the matrix in the SiCp/AZ31B composite suggested that submicron SiCp bonded well with the matrix without interfacial activity.     

Microstructure and properties of Sip/Al–Si surface composites prepared by ultrasonic method

Primary Si particles reinforced Al–Si surface composites (Si_p/Al–Si surface composites) were prepared by means of ultrasonic equipment with a special horn crucible. The microstructure and properties of the surface composites were investigated using optical microscope, scanning electron microscopy (SEM), hardness meter and friction and wear tester. The results show that when Al–12%Si alloy was treated by ultrasonic, Si element was easy to move up because of the decrease of the viscosity of the melt, and the alloy composition at the top of the melt became hypereutectic. So, a mass of primary Si particles formed in this place. The thickness of the surface composite layer in the surface composites decreased with increasing the ultrasonic input power. The average size of the primary Si particles in the surface composite layer was larger than that of Al–Si alloy untreated by the ultrasonic and increased with increasing ultrasonic input power. The top layer hardness of Si_p/Al–Si surface composites is higher than that of Al–Si alloy without ultrasonic treatment and increased with increasing ultrasonic input power. The friction coefficients of the top layers of the surface composites are lower than that untreated by ultrasonic. The friction coefficient decreased with increasing ultrasonic input power. With the increase of the applied load, the friction coefficient of the top layer of the surface composites increased. The wear mass loss of Si_p/Al–Si surface composites is lower than that Al–Si alloy without ultrasonic treatment. The wear resistance of the surface composites was improved with increasing ultrasonic input power.     

Synergistic effects of TiC and graphene on the microstructure and tribological properties of Al2024 matrix composites

Al matrix composites have attracted significant attention of researchers in recent years due to their lightweight, excellent mechanical and tribological properties. In this study, an Al2024 matrix hybrid composite (AMHC) reinforced with both TiC nanoparticles and graphene nanoplatelets (GNPs) was produced via a route of powder metallurgy. And its microstructure, microhardness and tribological properties are compared with those of unreinforced Al2024 alloy matrix and Al2024 matrix composites reinforced with either only TiC or GNPs. It was found that the distribution of Al₂Cu, TiC nanoparticles and GNPs in the matrix and the wear resistance are significantly improved when introducing both TiC nanoparticles and the GNPs. The wear mechanisms change from the adhesion-dominant wear for Al2024 and the other singly reinforced composites into abrasive-dominant wear for the hybrid composite. The significantly improved wear resistance of the AMHC is attributed to the synergistic effects of reinforcing and self-lubricating of the TiC and GNPs.     

SiCp/Al复合材料微弧氧化膜的组织结构及性能

采用微弧氧化技术对SiC体积分数分别为17vol%和55vol%的两种SiCp/Al复合材料进行处理。分析了两种材料微弧氧化膜的组织、形貌、相组成,测定了膜层的粗糙度、显微硬度、结合力,考察了膜层的耐磨和耐蚀性。结果表明:SiC的含量对SiCp/Al复合材料微弧氧化膜的表面形貌、粗糙度、相组成、结合力及摩擦磨损性能均有影响。17vol%SiCp/2009Al复合材料的微弧氧化膜较55vol%SiCp/6061Al复合材料更平整,微孔大小更均匀。55vol%SiCp/6061Al复合材料的微弧氧化膜的粗糙度(3.308 μm)比17vol%SiCp/2009Al复合材料(2.140 μm)大,表面熔融物堆积更多。两种材料的微弧氧化膜中均含有Al、Si、O、C、W等元素。55vol%SiCp/6061Al复合材料的微弧氧化膜中Mullite(SiO₂-Al₂O₃)相、α-Al₂O₃相、β-Al₂O₃相较多。17vol%SiCp/2009Al复合材料的微弧氧化膜的结合(38.55 N)较55vol%SiCp/6061Al(11.5 N)复合材料好。55vol%SiCp/6061Al复合材料的微弧氧化膜摩擦系数较大,磨损较严重。微弧氧化处理能有效改善两种SiCp/Al复合材料的耐蚀性。      

亚微米颗粒增强6061铝基复合材料的微塑变特性

发现亚微米级Ａｌ２Ｏ３ｐ／６０６１复合材料的微屈服抗力较高，组织稳定性良好，其微屈服抗力与微塑变符合Ｂｒｏｗｎ和Ｌｕｋｅｎｓ提出的线性规律；通过与ＳｉＣｐ／６０６１和ＡｌＮｐ／６０６１的微屈服行为与组织的对比分析，认为增强颗粒形状，尺寸以及基体中位错密度，亚晶粒尺寸等因素直接影响屈服抗力，亚微米级颗粒增强复合材料对尺寸稳定性要求来说，微观组织形态较合理，是较理想的精密仪表材料。     

SiCp颗粒增强铝基复合材料工艺与组织研究

对无压渗透制备碳化硅颗粒增强铝基复合材料工艺进行了探索，并利用光学显微镜、扫描电镜对其组织进行了观察，用ｘ射线衍射仪对复合材料组成相进行了分析。结果表明：采用无压渗透技术，可以制备碳化硅颗粒增强铝基复合材料；熔融的基体合金对碳化硅颗粒预制体渗透完全；其过程存在Ａｌ与ＳｉＣ的化学反应，产物为Ｓｉ和碳化铝（Ａ１４Ｃ３），其中Ｓｉ进入基体中，Ａｌ４Ｃ３能与大气中水汽发生化学反应，结果使碳化硅铝基复合材料存放一定时间后发生龟裂和粉化。为限制Ａｌ与Ｓｉ反应，可向基体中加入适量的Ｓｉ元素，可使电裂与粉化问题得到解决。     

SiCp/Al复合材料的磨损特性分析

本文研究了SiC颗粒增强铝基(ZL102)复合材料的磨损特性。结果表明,SiC颗粒的加入可提高材料的耐磨性,复合材料与基体合金相比,磨损速率相当低,而且其抗粘着磨损能力更强,磨损性能与增强相数量、分布及界面结合有关。      

不同颗粒度SiC增强铝基复合材料的切削加工性能与适用刀具

铝基复合材料中增强粒子的大小对复合材料的切削加工性能影响极大，本文研究了不同颗粒度碳化硅颗粒对铝基复合材料切削加工性能的影响。并分析了不同颗粒度碳化硅增强铝基复合材料所适用的刀具。探讨了切削刀具对不同大小颗粒碳化硅增强铝基复合材料的切削机理