轧制变形对网状结构TiB_w/Ti复合材料组织与力学性能的影响(英文)

通过反应热压技术成功制备出网状结构TiB晶须增强纯钛(TiBw/Ti)复合材料。原位合成的TiB晶须分布在大尺寸Ti基体颗粒周围形成网状结构。这种新型的网状结构TiBw/Ti复合材料表现出优异的综合力学性能。为了进一步改善力学性能及指导后续塑形变形加工,研究这种新型复合材料的轧制变形行为。结果表明:由于基体的形变强化,这种新型TiBw/Ti复合材料的强度可以通过轧制变形得到有效的提高,并且强度水平随着变形量的增加而增加。其中,通过轧制变形,可以使8.5%TiBw/Ti复合材料的强度从842MPa提高到 1030 MPa。需要指出的是,随着变形量的增加,TiB晶须的断裂程度也增加,这一点对复合材料的力学性能是不利的。     

热压烧结制备Al2O3/TiCN-Ni-Ti陶瓷复合材料的组织与性能

采用真空热压烧结方法制备Al2O3/Ti(C,N)-Ni-Ti陶瓷基复合材料,采用X射线衍射与扫描电镜分析材料的物相组成和显微结构,研究烧结工艺对材料物相组成、显微结构和力学性能的影响。结果表明:Ni和Ti的添加显著提高复合材料的强度和韧性;温度小于1 600℃时,复合材料的力学性能随热压温度的升高而升高;温度高于1 600℃时,温度升高及保温时间延长不仅会导致Al2O3晶粒的异常长大和Ti(C,N)的分解,而且会使Ni发生聚集现象,复合材料的力学性能下降;当烧结温度为1 600℃、保温时间为30 min时,制备的Al2O3/Ti(C,N)-Ni-Ti陶瓷复合材料的力学性能最佳,其相对密度达到99.4%,抗弯强度为820 MPa,断裂韧性达到9.3 MPa.m1/2。     

Effects of rolling deformation on microstructure and mechanical properties of network structured TiBw/Ti composites

TiB whiskers reinforced pure Ti (TiB_w/Ti) composites with a novel network microstructure were successfully fabricated by reaction hot pressing (RHP). TiB whiskers are in situ synthesized around the large pure Ti matrix particles, and subsequently formed into TiB_w network structure. The novel TiB_w/Ti composites with a network microstructure exhibit a superior combination of mechanical properties. In order to further improve the mechanical properties and guide the subsequent plastic forming, the rolling deformation behavior of the novel composites was investigated. The results show that the strength of the novel TiB_w/Ti composites can be effectively enhanced by rolling deformation due to the matrix deformation strengthening effect, and increased with increasing the rolling reduction. The strength of 8.5%TiB_w/Ti (volume fraction) composite is significantly increased from 842 MPa to 1030 MPa by rolling deformation. It is certain that the TiB whiskers are gradually broken with increasing the rolling reduction, which is harmful to the mechanical properties of the composites.     

Fabrication of ultrafine-grained AA1060 sheets via accumulative roll bonding with subsequent cryorolling

Ultrafine-grained (UFG) AA1060 sheets were fabricated via five-cycle accumulative roll bonding (ARB) and subsequent three-pass cold rolling (298 K), or cryorolling (83 K and 173 K). Microstructures of the aluminum samples were examined via transmission electron microscopy, and their mechanical properties were measured via tensile and microhardness testing. Results indicate that ultrafine grains in ARB-processed sheets were further refined by subsequent rolling, and the grain size became finer with reducing rolling temperature. The mean grain size of 666 nm in the sheets subjected to ARB was refined to 346 or 266 nm, respectively, via subsequent cold rolling or cryorolling (83 K). Subsequent cryorolling resulted in ultrafine-grained sheets of higher strength and ductility than those of the sheets subjected to cold rolling.     

Mechanical Properties and Microstructural Evolution of Bulk UFG Al 2014 Alloy Processed Through Cryorolling and Warm Rolling

Tensile properties,microstructural evolution and fracture toughness of A1 2014 alloy subjected to cryorolling followed by warm rolling(CR + WR)have been investigated in the present study.The solution-treated(ST)A1 2014 alloy is cryorolled followed by warm rolling process at different temperatures(110,170 and 210 ℃).The mechanical properties and microstructural features of deformed and undeformed A1 2014 alloys were characterised by optical microscopy,transmission electron microscopy(TEM)and scanning electron microscopy(SEM).The CR + WR samples at 170 ℃ showed an improved hardness(179 HV),tensile(UTS 499 MPa,YS 457 MPa)and fracture toughness(K_Q= 37.49 MPa m~(1/2),K_(ee) = 37.39 MPa m~(1/2) and J integral= 33.25 kJ/mm~2)with respect to ST alloy as measured from the tensile and fracture toughness test.The improved mechanical properties of CR + WR alloy are attributed to grain boundary strengthening,combined recovery and recrystallisation,precipitation hardening and dynamic ageing effect during the deformation.The precipitation of metastable spherical phase Al_2Cu was responsible for the improved tensile and fracture properties of finegrained A1 2014 alloy observed in the present work.     

成分和烧结温度对ZrO_2颗粒增强型钛基复合材料力学性能的影响

钛利用粉末冶金方法制备钛基复合材料。采用X射线衍射仪、金相显微镜、扫描电镜及力学性能测试仪研究材料成分和烧结温度对显微结构及性能的影响。结果表明：加入ZrO2颗粒能够提高粉末冶金钛基复合材料的力学性能。加入4%ZrO2,在1100°C下烧结4h,得到的钛基复合材料的相对密度为93.9%,屈服强度能达到1380MPa（比纯钛高570MPa）,并且具有良好的塑性（极限应变超过24%）。     

Enhanced Mechanical Properties of AA5083 Matrix Composite via Introducing Al0.5CoCrFeNi Particles and Cryorolling

High-entropy alloy particles (HEAPs) can markedly enhance the mechanical properties of metal matrix composites (MMCs). In this study, AA5083/Al_0.5CoCrFeNi HEAPs MMCs with different HEAPs contents (0, 1, and 3 wt%) were prepared via a stir-casting, and then these MMCs sheets were hot rolled (573 K) and cryorolled (77 K), respectively. The mechanical properties of the MMCs sheets were measured by tensile testing and microhardness test. Additionally, their microstructures were analyzed by scanning electron microscopy and transmission electron microscopy. Results revealed that the ultimate tensile strength (UTS) of the as-cast AA5083/Al_0.5CoCrFeNi HEAPs MMCs were improved from 203 to 257 MPa by adding 3 wt% HEAPs. And the mechanical properties of the MMCs sheets were improved after cryorolling. After cryorolling with 50% rolling reduction ratio, the MMCs with 1 wt% HEAPs had an UTS of 382 MPa, which was 1.9 times that of the MMCs before rolling. Finally, the strengthening mechanisms of HEAPs and cryorolling on the AA5083/HEAPs MMCs were discussed.     

冷轧制备AlSn20Cu/钢多层板的微观组织和力学性能（英文）

通过室温冷轧制备出了1060Al/AlSn20Cu/1060Al/钢多层复合板材,并探索了轧制压下量对复合板微观组织和力学性能的影响。利用扫描电子显微镜和电子背散射衍射（EBSD）对复合板微观组织进行表征,通过拉伸试验测量了复合板力学性能。复合板的初始轧制压下量为17%,最小稳定压下量为40%。结果表明,随着轧制压下量的增加,铝合金层中锡相和钢中组织沿轧制方向被拉长,但是纯铝层呈现出等轴晶。随着轧制压下量的增大,复合板抗拉伸强度和界面结合强度增加,而延伸率下降。AlSn20Cu合金层的断裂主要跟其中的锡相有关。     

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.     

Hot Roll Bonding of Aluminum to Twin-Roll Cast (TRC) Magnesium and Its Subsequent Deformation Behavior

In an experiment in which twin-roll cast AZ31 magnesium alloy and commercial purity aluminum (AA 1050) sheets were bonded by hot rolling as Al/Mg/Al laminate composites, it was found that increasing the preheating temperatures up to 400 °C enhances the bonding strength of composites. Further increases in the preheating temperatures accelerate the magnesium oxide growth and thus reduce the bonding strength. The influence of the reduction ratio on the bonding properties was also studied, whereby it was observed that increasing the rolling reduction led to an increase in the bonding strength. The experimental results show that the optimum bonding strength can be obtained at rolling temperatures of 375-400 °C with a 50-60% reduction in thickness. On the other hand, the subsequent deformation behavior of composite was assessed using plane strain compression and deep drawing tests. We demonstrate that the composites produced using the optimum roll bonding conditions exhibited sufficient bonding during subsequent deformation and did not reveal any debonding at the bonding interface.     

Effect of ageing on microstructure and mechanical properties of bulk, cryorolled, and room temperature rolled Al 7075 alloy

The effect of ageing on mechanical properties and microstructural characteristics of a precipitation hardenable Al 7075 alloy subjected to rolling at liquid nitrogen temperature and room temperature are has been investigated in the present work employing hardness measurements, tensile test, XRD, DSC, and TEM. The solution-treated bulk Al 7075 alloy was subjected to cryorolling and room temperature rolling to refine grain structures and subsequently ageing treatment to simultaneously improve the strength and ductility. The solution treatment combined with cryorolling up to a true rolling strain of 2.3 followed by low temperature ageing at 100 °C for 45 h has been found to be the optimum processing condition to obtain fine grained microstructure with improved tensile strength (642 MPa) and good tensile ductility (9.5%) in the Al 7075 alloy. The combined effect of suppression of dynamic recovery, partial grain refinement, partial recovery, solid solution strengthening, dislocation hardening, and precipitation hardening are responsible for the significant improvement strength-ductility combination in the cryorolled Al 7075 alloy subjected to peak ageing treatment. The cryorolled and room temperature rolled Al 7075 alloy, upon subjecting to peak ageing treatment, have shown higher strength and ductility in the former than the latter. It is due to presence of high density of nanosized precipitates in the peak aged cryorolled sample.     

双步球磨和放电等离子烧结TiAl基合金的显微组织和力学性能(英文)

采用双步球磨法和放电等离子烧结技术制备细晶Ti-45Al-2Cr-2Nb-1B-0.5Ta-0.225Y(摩尔分数,%)合金,并研究烧结温度、显微组织和力学性能之间的关系。结果表明:双步球磨粉末的颗粒形状较规则,其颗粒尺寸为20～40μm,主要由TiAl和Ti3Al相组成。放电等离子烧结后的块体由主相TiAl、少量的Ti3Al相及Ti2Al和TiB2相组成。当烧结温度为900°C时,烧结块体获得的主要组织是等轴晶组织,等轴晶粒尺寸大多数在100~200nm的范围内,合金的压缩断裂强度为2769MPa,压缩率为11.69%,抗弯强度为781MPa;当烧结温度为1000°C时,等轴晶粒明显长大,TiB2相明显增多,合金的压缩断裂强度为2669MPa,压缩率为17.76%,抗弯强度为652MPa。随着烧结温度的升高,合金的维氏硬度由658降低到616。压缩断口形貌分析表明,合金的断裂方式为沿晶断裂。     

Effect of rolling on interfacial property of steel/mushy Al-20Sn bonding plate

1　INTRODUCTIONSteel/Al 2 0Snbondingplateisidealmaterialforneotypebearing[1] .Itiswidelyusedinthefieldssuchasmachinery ,automobile ,etc[2 5] .Forthisbondingplate ,twothingsareveryimportant.Oneisthedis tributionofSnparticlesinAl 2 0Snlayer ,theotheristheinterfacialshearstrength .Theformerdeterminesthelifeofbonding plate .Thelatterdeterminesthesafetyofbondingplate .TheevenerthedistributionofSnparticlesinAl 2 0Snlayer ,thelongertheusagelifeofbondingplate .Thelargertheinterfacialshearstr…     

热加工工艺对钛-钢复合板界面力学性能和显微组织的影响

研究了热加工工艺对钛-钢复合板界面力学性能和显微组织的影响。测试了在A，B，C，D4种温度下热轧复合板界面的力学性能，用金相显微镜及扫描电镜观察了界面显微组织并分析了界面的成分。结果表明，在A，B2种温度下轧制的钛-钢复合板界面机械性能良好，延伸率高，其剪切强度不但可保持坯料原有的水平，甚至还略有增加。在C，D2种温度下轧制的钛-钢复合板界面机械性能相对较低，延伸率较高，但剪切强度要比爆炸复合坯料低，尤其是D加热温度，轧制后界面剪切强度急剧下降。热轧的终轧温度也是影响钛-钢复合板界面结合性能的重要因素。在低于相转变温度的合适温区热轧，且终轧温度合适，获得的钛-钢复合板结合界面无爆炸波纹，没有污染，生产的脆性化合物极细小，组织类同于钛材完全退火的等轴组织。     

极限规格热轧高强耐候钢的开发

通过中C、高Ti成分设计,采用合理的控制轧制和控制冷却工艺,充分发挥Ti的析出强化和细晶强化作用,在首钢迁钢2 250 mm热连轧生产线上开发出综合力学性能优异的薄宽规格（4 mm×1 800 mm）热轧高强耐候钢,其力学性能：ReL≥750 MPa,Rm≥900 MPa,A≥16%,工艺成本低,生产效率高。     

基于仿生结构的Al-Ti-Ti2AlNb层状复合材料的组织与力学性能

受生物材料的韧脆复合结构的启发,本文将Al箔、Ti箔和Ti2AlNb箔材堆叠排列,采真空热压烧结技术制备了层级结构的Al-Ti-Ti2AlNb层状复合材料。利用SEM、XRD等技术表征了材料的微观结构,并测试了抗弯与抗压性能。研究发现,本文设计的层状结构复合了Ti、TiAl系列间化合物、Ti2AlNb等多种材料,层级结构明显,界面清晰。抗弯强度与抗压强度分别为1231±71MPa和1341±63MPa,相比同类材料具有显著的优势。分析认为,多层级结构的存在对裂纹的扩展有显著地阻碍作用;相比常规的二元TiAl层状材料,Ti2AlNb层的存在显著提高了力学性能。     

钛对碳纳米管增强铝基复合材料组织与性能的尺寸效应

通过粉末冶金的方法,制备了致密和较高强度的CNT/Al复合材料,并系统地研究了在制备粉末阶段时引入不同粒径的钛粉后,对复合材料的组织结构与力学性能的影响。结果表明,在一定范围内,钛颗粒尺寸与制备的CNT-Ti/Al复合材料力学性能成反比。当加入的钛颗粒粒径为80 nm时,CNT-Ti/Al复合棒材力学性能最佳。其主要原因包括两个方面:一是钛颗粒有助于碳纳米管的分散,同时自身作为一种第二相强化基体;二是制备过程的热反应,使复合材料组织中生成了一种核壳结构,极大地增强了其界面结合与碳纳米管的载荷转移。     

采用铌中间层的钛合金与不锈钢的真空热轧连接界面的显微组织及性能

进行了钛合金与不锈钢采用铌中间层的真空热轧连接实验,分析了连接界面的显微组织及性能。结果表明,采用铌中间层能够明显提高接头的塑性。当压缩率为25%,轧制速度为38 mm/s,热轧温度为800°C和900°C时,不锈钢与铌的连接界面没有明显的金属间化合物层;当热轧温度为1000°C和1050°C时,不锈钢与铌连接界面形成Fe-Nb金属间化合物层,并且当热轧温度为1050°C时在金属间化合物层与不锈钢之间出现开裂。铌与钛合金连接界面的扩散层厚度随着热轧温度的升高而增大。热轧温度为900°C的连接接头的拉伸强度可达-417.5MPa,拉伸试样断裂于铌中间层,断口呈塑性断裂特征。热轧温度为800°C的热轧过度接头分别与钛合金和不锈钢进行TIG焊接,TIG焊后热轧过度接头的拉伸强度可达-410.3 MPa,拉伸试样断裂于铌中间层,断口呈塑性断裂特征。     

轧制变形量对GNPs/Ti复合材料组织与性能的影响

本文采用放电等离子烧结技术(SPS)和热轧制备了石墨烯/钛基复合材料(GNPs/Ti)。重点研究了轧制变形量对GNPs/Ti复合材料的显微组织及力学性能的影响规律。采用扫描电镜观察不同变形量后的显微组织,结果显示,随着轧制变形量的增加,基体晶粒长径比增大,石墨烯取向性提高。拉伸结果表明,GNPs/Ti复合材料的抗拉强度和断后伸长率随着变形量的增加而增加,最大抗拉强度达到680MPa,相比纯钛提高了33%。采用轧制工艺可以使GNPs/Ti复合材料孔洞减少、GNPs分布具有取向性,从而提高材料的力学性能。     

Fe基非晶合金增强1060铝基多层复合材料的组织与性能

采用累积叠轧焊+中间退火法复合轧制1060Al/Fe基非晶多层铝合金复合板材。利用光学显微镜、扫描电镜、X-衍射分析仪以及拉伸试验机分析Al基复合材料的微观组织结构变化、断口形貌、物相组成以及力学性能。结果表明:Fe基非晶复合材料的增强体在300 ℃中间退火过程中发生部分晶化,在累积变形轧制过程中发生破碎,并随着变形道次的增加,破碎程度随之增大;复合板前6道次的累积轧制变形出现了明显的加工软化现象,并且随着变形道次的增加,其加工软化的效果愈明显;随着累积轧制变形道次增加,Al基复合材料的力学性能发生了明显的变化,第2道次轧制变形后屈服强度与抗拉强度达到了最大值为140 MPa和156 MPa,伸长率为5.53%,达到最佳综合性能。