搅拌参数对半固态搅拌工艺制备(ABO_w+SiC_p)/6061Al复合材料微观组织和力学性能的影响(英文)

采用不同半固态机械搅拌工艺(变化搅拌温度和搅拌时间),制备硼酸铝晶须(ABOw)和碳化硅颗粒(SiCp)混杂增强6061铝基复合材料。利用扫描电镜(SEM)、X射线衍射(XRD)、透射电镜(TEM)和拉伸试验研究搅拌工艺参数对复合材料微观组织和力学性能的影响。结果表明:在可以搅拌的情况,增强体在复合材料中分布的均匀性和复合材料的力学性能随着搅拌温度的降低和搅拌时间的延长而得到提高。基于对复合材料微观组织的观察和力学性能的测试得到最佳的搅拌工艺参数为:搅拌温度640℃,搅拌时间30min。     

Mg对无压自浸渗制备SiCp/Al复合材料组织与性能的影响

采用无压自浸渗法制备SiCp/Al复合材料。研究了Mg含量对SiCp 与Al之间浸润性的影响 ;探讨了Mg含量对SiCp/Al复合材料的组织与性能的影响及其作用机理。结果表明 ,加入的Mg与SiCp 表面的氧化物薄膜和铝基体发生反应 ,生成物会阻止SiCp 与Al基体反应生成Al4 C3 脆性相 ,同时SiCp 表面的微反应也增加了基体与SiCp 的结合强度 ,改善了基体与SiCp 之间的浸润性 ,从而使复合材料的耐磨性提高了 3～ 4倍。     

超声波搅拌功率对原位自生Mg_2Si/Al基复合材料凝固组织和力学性能的影响

采用超声波搅拌方法制备了原位自生Mg_2Si/Al基复合材料,研究了超声波功率对复合材料凝固组织和力学性能的影响。结果表明:超声波搅拌不但能够细化初生Mg_2Si颗粒,改变凝固组织形貌,而且具有除气除杂功能,二者共同提高了Mg_2Si/Al基复合材料的力学性能。在本实验条件下:超声波功率为150 W时,Mg_2Si/Al基复合材料抗拉强度最高,为178 MPa;而伸长率则在超声波功率为100 W时最好,为4.94%。     

SiCp在Mg-Zn-Ca-Mn复合材料的力学性能及微观结构的影响

在目前的研究中,利用搅拌铸造结合超声处理方法成功的制备出了不同体积分数（5 和10 vol.%）的微米颗粒增强的AZ31B镁基复合材料。利用350℃,12:1的挤压比对铸锭进行了挤压处理。利用金相和扫描电子显微镜两种不同体积分数的SiCp被选做为增强体,利用半固态结合超声处理法制备了Mg-Zn-Ca-Mn复合材料,然后在350℃用15:1的挤压比进行了热挤压。利用OM、SEM和TEM对材料的微观结构进行了检测。热挤压后的微观结构显示SiC颗粒的分布较为均匀且在1vol.% SiCp/Mg-Zn-Ca-Mn 和 3vol.% SiCp/Mg-Zn-Ca-Mn复合材料中晶粒被显著细化。SiCp的引入可以改善0.2%屈服强度和抗拉强度。屈服强度和抗拉强度是随着颗粒含量的增加而增加。     

Cu和Mg含量对Al-Cu-Mg-Ag合金组织与性能的影响

通过力学试验及透射电镜研究了不同Cu和Mg含量对Al-Cu-Mg-Ag合金室温、高温力学性能以及显微组织的影响.结果表明,提高Cu和Mg的含量可以提高合金在室温及高温条件下的屈服强度和抗拉强度,但伸长率下降.透射电子显微分析表明,增加Cu和Mg的含量将提高时效过程中强化相的形核密度与体积分数,从而提高合金的强度.     

TiB_2含量对原位反应合成TiB_2/B_4C复合材料的组织结构和力学性能的影响(英文)

以B4C,TiO2和石墨粉为原料,采用原位反应热压烧结工艺(2050℃,35MPa,1h)制备了致密的TiB2含量为10%～40%(体积分数)的TiB2/B4C复合材料,并对复合材料的组织结构和力学性能进行了研究。扫描电子显微镜和透射电子显微镜分析结果表明:在B4C晶内及晶界处均匀分布着纳米或亚微米级的TiB2颗粒,随着TiB2含量的增加,弹性模量和断裂韧性明显增大,而弹性模量和抗弯强度却随之减小。40%(体积分数)TiB2/B4C复合材料具有高的断裂韧性,高达8.2MPam1/2,主要增韧机制由微裂纹增韧和裂纹偏转增韧。     

Microstructure and mechanical properties of Al-Fe-V-Si/SiCp composites

The characteristics of microstructures and mechanical properties of the multi-layer spray deposited SiCp/A1-6.SFe-0.6V-1.3Si, SiCp/A1-8.SFe-1.3V-1.7Si and SiCp/Al-10Fe-1.3V-2Si composite sheets obtained by rolling after extruding were investigated. The evolution of the grain and phases of these composites during processing were examined, and the influence of the microstructures on the mechanical properties was analyzed. The experimental results show that the ultimate tensile strengths σb of the three kinds of composite sheets are 420, 535, 470 MPa respectively at room temperature, and 232, 285, 300 MPa at 315℃ and 148, 180, 200 MPa at 400 ℃. The excellent mechanical properties can be attributed to the high solid solubility, fine grain size, Al12（Fe,V）3Si precipitation particles and the SiC particles. And the composition of the matrix alloy has an obvious effect on the mechanical properties of the as-rolled sheets.     

预变形量对7075合金半固态组织与性能的影响

利用应变诱发熔化激活(SIMA)法制备了7075合金半固态坯料,分析了预变形量对坯料的显微组织及室温压缩性能的影响,研究了不同预变形量下的半固态坯料的室温压缩变形能力。结果表明,预变形量越大,7075合金半固态坯料的初生α-Al固相颗粒越细小、球形率越好,液相率越高,抗压强度与屈服强度随之逐渐升高;预变形量值达到12%以后,半固态组织形态与压缩力学性能都趋于稳定。同时,预变形量的增加,可有效提高7075合金半固态坯料的室温压缩变形能力,当预变形量达到12%以上时,坯料的塑性变形能力较强。     

Effect of Sb on microstructure and mechanical properties of Mg2Si/Al-Si composites

The effect of Sb on the microstructure and mechanical properties of Mg2Si/Al-Si composites was investigated.The results show that Sb can improve the microstructure and mechanical properties of Mg2Si/Al-Si composites.When the content of Sb is 0.4%,the morphology of primary Mg2Si changes from dendrites to fine particles,the average size of Mg2Si particles is refined from 52 to 25μm,and the ultimate tensile strength and elongation of the composites increase from 102.1 MPa and 0.26% to 138.6 MPa and 0.36%,respectively.The strengthening mechanism can be attributed to the fine-grain strengthening.However,excessive Sb is disadvantageous to the modification of the composites.     

Processing, microstructure and mechanical properties of magnesium matrix nanocomposites fabricated by semisolid stirring assisted ultrasonic vibration

Particulate reinforced magnesium matrix nanocomposites were fabricated by semisolid stirring assisted ultrasonic vibration. Compared with the as-cast AZ91 alloy, the grain size of matrix alloy in the SiCp/AZ91 nanocomposite stirring for 5 min was significantly decreased due to the addition of SiC nanoparticles. SiC nanoparticles within the grains exhibited homogeneous distribution although some SiC clusters still existed along the grain boundaries in the SiCp/AZ91 nanocomposite stirring for 5 min. With increasing the stirring time, agglomerates of SiC nanoparticles located along the grain boundaries increased. The ultimate tensile strength, yield strength and elongation to fracture of the SiCp/AZ91 nanocomposite stirring for 5 min were simultaneously improved compared with the as-cast AZ91 alloy. However, the ultimate tensile strength and elongation to fracture of the SiCp/AZ91 nanocomposite decreased with increasing the stirring time.     

Compressive deformation of semi-solid SiC_p/ZA27 composites

1　INTRODUCTIONTheapplicationofcastingSiCp/ZA2 7compositesisgreatlylimitedduetotheinhomogeneousdistribu tionofSiCpandtheporosityexistedinthematrix[1] .However,semi solidformingtechnology (SSF )e mergedintherecentyearscannotonlydecreaseore liminatetheporosityandenhancethecompactnessofthematrix ,butalsoimprovetheuniformdistributionofthereinforcementthroughtheredistributionofthereinforcementfromitsuniquecharacteristicsofmouldfilling[2 ] .Inaddition ,SSFisanearnet shapeform ingtechnology …     

半固态搅拌工艺参数对铝-铜合金显微组织和力学性能的影响

采用不同的工艺参数制备半固态铝合金坯料,并对铝合金的金相组织、抗弯强度和硬度进行测量,评估工艺参数对铝合金材料力学性能的影响。研究表明,机械搅拌铝合金的最佳工艺参数是搅拌速度900r／min,搅拌时间2min,搅拌时温度630℃。半固态细小、均匀和圆整的组织结构与普通铸造的相比,其抗弯强度可以提高26％,硬度提高8％,合金的力学性能得到改善。     

旋转摩擦挤压法制备Al-Mg合金的组织和力学性能

采用旋转摩擦挤压法(RFE)制备了不同Mg含量的Al-Mg铝合金,对其进行力学性能测试和显微组织观察.结果表明:退火态的5A06基材经RFE加工后,晶粒明显细化,抗拉强度和伸长率同时提高.采用5A06和AZ31B为基材经RFE加工制备Al-Mg合金后,合金抗拉强度随Mg含量的增加而增加,但伸长率却随合金Mg含量的增加而...     

半固态搅拌工艺参数对铝-铜合金显微组织和

采用不同的工艺参数制备半固态铝合金坯料,并对铝合金的金相组织、抗弯强度和硬度进行测量,评估工艺参数对铝合金材料力学性能的影响.研究表明,机械搅拌铝合金的最佳工艺参数是搅拌速度900 r/min,搅拌时间2min,搅拌时温度630℃.半固态细小、均匀和圆整的组织结构与普通铸造的相比,其抗弯强度可以提高26%,硬度提高8%,合金的力学性能得到改善.     

Effect of particle size on thermo-physical properties of SiC_p/Cu composites fabricated by squeeze casting

For the electronic packaging applications, copper matrix composites reinforced with different sized SiC particles (10 μm, 20 μm and 63 μm) were fabricated by squeeze casting technology. And the effect of particle size on their thermo-physical properties was discussed. The composites are free of porosity and the SiC particles are distributed uniformly in the composites. It is found that the mean linear thermal expansion coefficients(20 - 100 ℃ ) of SiCp/Cu composites are in the range of (8.4 - 9.2) × 10-6/℃, and smaller expansion coefficient can be obtained for the composites with finer SiC particles because of the larger restriction in expansion through interfaces. Their thermal conductivities are reduced with the decrease of SiC sizes. This is attributed to the fact that the negative effect of interfacial thermal resistance becomes increasingly dominant as the particles becomes smaller.     

高强Al-Mg合金钨极氩弧双丝增材制造工艺与组织性能

针对钨极氩弧增材制造铝合金构件效率低的不足,采用二根同质铝镁合金丝材同步送进同一熔池的增材制造方式,从而达到高效率高质量制造高强铝镁合金构件的目的.试验中分别采用单填丝和双填丝钨极氩弧工艺,分别制造了直壁体试样,对比试验研究了二种工艺增材制造试样在宏观尺寸、显微组织和力学性能上的差异.结果表明,在相同的工艺参数条件下,双填丝增材制造工艺熔敷速率是单填丝工艺的2.08倍,试样的晶粒明显更加细小;所制造试样的抗拉强度达到铸造7A52铝镁合金的71%,纵向抗拉强度相对单填丝提高了7%,纵向断后伸长率提高了5%.     

Effects of electromagnetic stirring on microstructure and mechanical properties of super light Mg-Li-Al-Zn alloy

Effects of electromagnetic stirring on the microstructure and mechanical properties of the magnesium-lithium-aluminum alloy were studied.The results reveal that,the morphology of theαphase changes from the long block to globular structure andβ phase distributes more widely in the periphery ofαphase when the electromagnetic stirring voltage is higher than 110 V.The mechanical properties are increased significantly with the increasing electromagnetic stirring.The tensile strength is improved from 172 to 195 MPa,and the elongation is increased from 10.65%to 25.75%.     

Cu含量对重力铸造Al-Cu-Mg-Sc合金组织及力学性能的影响

在重力铸造条件下制备了不同Cu含量(4%~6%,质量分数,下同)Al-Cu-Mg-Sc合金,采用500 ℃×4 h＋520 ℃×6 h的双级固溶,水冷后进行175 ℃×5 h时效。通过维氏硬度测试、室温拉伸性能测试试验、扫描电镜分析(SEM)等手段,研究了不同Cu含量对试验合金显微组织和力学性能的影响,进而优化Al-Cu-Mg-Sc铝合金成分。结果表明,经热处理后,随Cu含量从4.26%提高至5.58%,Al₂Cu析出相含量持续提高,热处理后合金屈服强度从191 MPa提升至216 MPa,抗拉强度从323 MPa提升至355 MPa,伸长率维持在13%附近。然而,当Cu含量较高时(6.13%),微观组织中Al₂Cu相体积分数较高,固溶后进入基体的Al₂Cu相数目有限,有大量Al₂Cu相残留在晶界处,经过时效处理后,合金的强化效果不能随Cu含量的增加而继续提升。因此整体上,随Cu含量提高,时效态高Cu含量合金的硬度和抗拉强度先增加随后趋于平稳,断后伸长率呈现先增加后降低的规律。Cu含量为5.58%的铸造Al-Cu-Mg-Sc铝合金时效后获得最佳综合性能,其硬度为117 HV,抗拉强度和屈服强度分别为355 MPa、216 MPa,断后伸长率为13.5%。     

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。     

Vibration assisted brazing of SiCp/A356 composites: microstructure and mechanical behaviour

Abstract

Vibration assisted brazing of SiCp/A356 composites in air was investigated. A vibration was applied on one of the samples to be bonded at 375°C during brazing. The filler metal was extruded reciprocally and impacted intensively and reciprocally on the two surfaces of the base materials during vibrating. It can be found that most of the oxide film on the surface of the composites was disrupted and removed through the observation by SEM. The metallurgical bonds formed between the filler metal and the base materials. However, a lot of porosities were entrapped in the bond metal. A vibration was once more applied after the samples were continuously heated up to 520°C, and any porosity could not be found. The bonds mainly composed of a new alloy, which have a higher content of aluminium and free of porosities, show a higher shear strength of 178 MPa comparing to that of the base materials.