变形处理对Al-Ti-C中间合金的影响

研究了变形处理对Al-Ti-C中间合金细化效果的影响。研究表明，采用不同的变形手段对Al-Ti-C中间合金变形以后，其细化效果明显下降，而且随变形量的增加，细化效果下降愈严重。作者分析了变形后Al-Ti-C中间合金的微观组织，发现变形后TiAl3相呈断裂状态，而且在TiAl3相内部分布的TiC颗粒与其分离开来。作者认为这是造成Al-Ti-C中间合金细化效果下降的主要原因。     

TiC弥散强化铁基合金粉末的研究

ＴｉＣ弥散强化铁基合金粉末的研究吴军，王成国，孙康宁（山东工业大学）机械合金化是通过高能球磨使材料实现固态反应而合金化的一种方法。它是６０年代末期为研制氧化物弥散强化的高温合金而提出的［１］，近年来也出现了碳化物弥散强化材料的研究报道［２～５］。目前...     

Fe40Al/TiC复合材料的高温氧化特性

用自发熔渗法制备了TiC基Fe40Al金属间化合物复合材料。用氧化增重方法，研究了Fe40Al／80vol％-88vol％TiC复合材料在700℃-1100℃的恒温空气中的氧化动力学，并借助SEM／EDS和XRD等手段研究了氧化过程中材料微观组织结构的演变及材料表面粗糙度对氧化特性的影响。复合材料的氧化增重和氧化时间呈幂函数关系，幂指数约为0．63—0．75，氧化速率随着氧化时间的延长而降低。氧化层主要由致密的TiO2组成，TiO2颗粒的尺寸与氧化温度和材料表面粗糙度有关。     

原位自生成TiC／Ti基复合材料的高温氧化

利用热重分析(TGA)测量了原位生成的TiC／Ti-6Al复合材料在600，700和800℃下经连续20h的氧化增重特性，利用SEM，EDS和XRD研究了复合材料经氧化试验后表面氧化层的结构，相组成及成分。结果表明，原位生成的Ti基复合材料在高温氧化时遵循抛物线规律在800℃时的氧化增重量远大于600℃和700℃时的，计算获得该复合材料的氧化激活能为255．7kJ／mol。研究发现经20h的600℃或700℃氧化形成的氧化物呈现不连续的岛屿状，主要成分为金红石型的Ti02，而在800℃氧化20h后，氧化物是均匀连续的致密膜，由TiO2，A12O3组成。该复合材料的氧化首先发生在TiC颗粒的表面上，而不是象均质Ti材料一样氧化在整个表面上均匀地发生。     

多层氩弧熔敷含TiC颗粒增强涂层的微观组织及耐磨性能

利用多层多道钨极氩弧熔覆技术,熔融预涂于钢基体表面钛铁和石墨混合粉末,可以在普通碳钢表面获得综合性能优异的复合材料表面熔敷层;测试和分析表明,熔敷层微观组织主要由铁素体、低碳马氏体、原位生成的TiC颗粒及碳化物等组成;熔敷层表面硬度达到了HRC 57以上,呈梯度分布特征;滑动磨损试验表明,由于TiC增强颗粒的存在,熔敷层与摩擦副的摩擦系数在磨损过程中不稳定,变化范围较大;TiC颗粒对摩擦的阻碍、钉扎作用大大提高了熔敷层的抗磨损性能,熔敷层磨损体积比基体金属小15～20倍,具有良好的耐磨性能.     

铸造Fe/TiCp复合材料的显微组织和力学性能

通过感应熔炼铸造法制备了一种Fe／TiCp复合材料，采用X-射线衍射、光镜和扫描电镜及能谱分析研究了其铸态和850℃退火态的显微组织和力学性能。结果表明：铸态复合材料的显微组织由珠光体基体和均匀分布的立方状TiC颗粒组成，TiC颗粒与基体界面洁净，抗拉强度817MPa，伸长率2．8％，硬度33．2HRC；经850℃退火后，基体转变为铁素体和珠光体，TiC颗粒形貌基本不变，强度和硬度较铸态有所降低，伸长率略有升高。     

Characterization of in situ synthesized TiC particle reinforced Fe-based composite coatings produced by multi-pass overlapping GTAW melting process

In this paper, in situ synthesized TiC particles reinforced Fe-based surface composite coatings by multi-pass overlapping gas tungsten arc welding (GTAW) melting process employing a proper amount of graphite and ferrotitanium (FeTi) on AISI 1020 steel substrate was produced. The microstructure and wear properties of the composite coatings were investigated by means of an electron microprobe microanalysis (EPMA), X-ray diffractometer and wear tester. The results showed that the multi-pass overlapping GTAW melting surface composite coatings can be obtained under suitable welding parameters, and no crack and porosity are found in the tracks. The X-ray and EPMA results confirm that TiC particles can be formed via reaction of FeTi and graphite during multi-pass overlapping GTAW melting process. TiC particles present cubic and dendrite shape in the non-overlapping zone. It is found that there occurred TiC particles coarsening at the overlap regions, which can lead to detrimental effects on the hardness and wear performance. Composite coatings give a high hardness and excellent wear resistance; and the wear friction coefficient of the coating is less than that of the 1020 steel. As a result, multi-pass overlapping GTAW melting process can be used effectively for producing surface composite coatings with a pre-placed powder to improve wear resistance of the AISI 1020 steel.     

High-velocity oxyfuel reactive spraying of mechanically alloyed Ni-Ti-C powders

Recently, there has been considerable interest in producing cermet coatings with nanoscale carbide grains in the size range 50 to 500 nm. In this article, the production of nanoscale TiC grains in a Ni-based alloy matrix by reactive high-velocity oxyfuel (HVOF) spraying of metastable Ni-Ti-C powder is reported. Mechanical alloying of a Ni(Cr) prealloyed powder and Ti and C elemental powders was performed in a planar-type ball mill, and materials were characterized in detail using x-ray diffraction (XRD) and scanning electron micros-copy (SEM). Phase changes were correlated with milling time and other processing conditions. Results show that, by the selection of appropriate conditions, a metastable Ni-Ti-C powder could be obtained with the nominal composition 50wt.%Ni-40wt.%Ti-10wt.%C. Following sieving and classification, powder was produced with a particle size range of −38 to 8 μm, which is suitable for HVOF spraying. Coatings, approximately 250 μm thick, were deposited by HVOF spraying onto mild steel substrates, and the microstructures formed were investigated. XRD showed that a self-propagating high-temperature synthesis (SHS) reaction had occurred in the powder particles during spraying and that the principal phases present in the coating were TiC and a Ni-rich solid solution; small quantities of NiTi, TiO₂, and NiTiO₃ were also present. SEM revealed that the coatings had a characteristic, splatlike morphology and that TiC formed as a nanoscale dispersion, with a size range of ∼50 to 200 nm, within solidified splats. The microstructures of these reactively sprayed Ni-TiC coatings are briefly compared with those observed in HVOF-sprayed coatings deposited using prereacted SHS powder. The original version of this paper was published as part of the ASM Proceedings, Thermal Spray 2003: Advancing the Science and Applying the Technology, International Thermal Spray Conference (Orlando, FL), May 5–8, 2003, Basil R. Marple and Christian Moreau, Ed., ASM International, 2003.     

Ti/Nb作中间层脉冲加压扩散连接TiC金属陶瓷与不锈钢

用Ti/Nb作中间层,在温度890℃、时间4~12min、脉冲压力2~10MPa、频率f=0.5Hz、恒压10MPa下,对TiC金属陶瓷和304不锈钢(304SS)进行脉冲加压与恒压扩散焊,获得了牢固的固相扩散焊接头。通过扫描电镜SEM、能谱EDS、X射线衍射XRD与剪切性能测试,对接头的显微组织、界面产物与强度进行分析。结果显示:两种接头的界面物相相似,主要有σ相,(β-Ti,Nb)与α+β-Ti固溶体。连接时间10min时,恒压下的TiC/304SS接头抗剪强度为55.6MPa,而脉冲加压下的接头抗剪强度达110MPa。恒压下接头断裂方式为TiC陶瓷断裂,而脉冲压力下接头断裂方式为TiC陶瓷与界面产物间交替进行的混合断裂。     

用于纤维材料表面耐磨涂层的制备与性能表征

为使涤纶织物应用范围更广,更耐磨,本文制备了一种有机硅树脂基纳米硼化钛碳化钛复合涂层,通过正交实验法得到最佳的涂层方案,并尝试将其应用于涤纶织物,以改善涤纶织物的表面结构,进而实现涤纶织物表面优异的耐磨性能.为测试涂层对涤纶织物性能的影响, 采用泰伯式耐磨仪、液滴形状分析仪、电子织物强力机、扫描电子显微镜(SEM)研究了涂层织物的耐磨性能、疏水性能、物理机械性能和磨损织物的表面微观形态.研究表明：当有机硅树脂与无水乙醇质量比为75: 25,含量(质量分数)为93%;超分散剂含量为1.5%;乙醇增稠剂含量为1.5%;纳米硼化钛和碳化钛质量比为2: 1,含量为4%时,所得涂层溶液应用于涤纶织物后会形成一层包覆层,耐磨性能最优.对于涂覆量为15 g/m²的涤纶,拉伸断裂强力由573.92 N提高到620.48 N,顶破强力由652.34 N提高到790.07 N,撕裂强力由9.87 N降低到5.78 N,疏水性能有较大提高,接触角可达到120°以上.