Ti—Code12合金焊后腐蚀性能研究

对Ｔｉ－Ｃｏｄｅ１２合金在低浓度ＨＣｌ，高浓度沸腾ＭｇＣｌ２及沸腾１０％次氯酸钙介质中耐焊区腐蚀性能进行了研究。结果表明：Ｔｉ－Ｃｏｄｅ１２合金焊后在上述介质中为均匀腐蚀。焊后经适当热处理耐蚀性明显提高。其耐蚀机理为：在α基体上均匀分布着Ｔｉ２Ｎｉ相。该相在低浓度还原性介质中优先溶解及Ｎｉ＾＋＋离子重新沉积，促进α基体钙化进而提高了合金耐均匀腐蚀性能。     

一种新型双相热模钢的组织性能研究

介绍了一种新型铁基高温合金ＧＨ８６０７，经过固溶时效处理，获得了α／γ双相基体和弥散分布的Ｌａｖｅｓ相、Ｍ６Ｃ等强化相；该合金有良好的高温力学性能、物理性能和抗氧化性能，在弹体成形拔伸模具应用中，取得了显著成效。     

一种新型双相热模钢的组织性能研究

介绍了一种新型铁基高温合金ＧＨ８６０７，经过固溶时效处理，获得了α／γ双相基体和弥散分布的Ｌａｖｅｓ相、Ｍ６Ｃ等强化相；该合金具有良好的高温力学性能、物理性能和抗氧化性能．在弹体成形拔伸模具应用中，取得了显著成效．     

Al-Zn-Mg-Sc合金连续冷却转变曲线的测定

测定了Al-Zn-Mg-Sc合金固溶处理后的连续冷却转变（CCT）曲线,通过动态电阻法测得冷却过程的电阻-温度曲线,根据曲线斜率的变化规律确定相变开始点、结束点以及临界冷却速度范围,绘制出该合金的CCT图,通过扫描电镜和透射电镜分析观察连续冷却过程的组织转变.结果表明,动态电阻法测得的CCT图是可信的;在470℃,保温1 h固溶处理后,抑制相变发生的临界冷速在2 168.0℃/min以下,但高于716.8℃/min,相变主要集中在150~420℃的温度区间发生;当冷却速度较慢时,平衡相η在晶内和晶界大量析出并逐渐长大和粗化,当冷却速度较快时,合金保持了较高的过饱和度,冷却到70℃以下仍有相变发生.     

时效对Ti3Al—Nb合金显微组织与拉伸性能的影响,

研究了Ｔｉ３Ａｌ－Ｎｂ（Ｔｉ－２４Ａｌ－１４Ｎｂ－３Ｖ－０．５Ｍｏ）ａｔ％）合金时效过程中组织与性能的变化，结果表明，合金经α２＋β两相区１０００℃ｌｔ／ＷＱ固溶处理后，分别在６５０、７５０和８５０℃哩效２４ｈ空冷，会使其析出二次针状α２相和大量“Ｏ”相，随着时效温度的升高，实姓α２相长大，二次针状α２相和“Ｏ”相球化。“Ｏ”相除以块状形式存在于初生α２相周围外，还成片分布于初生α２相内部。时效温     

Ti3Al基金属间化合物的疲劳裂纹扩展与断裂

研究了Ｔｉ３Ａｉ－Ｎｂ系合金经三种固溶和稳定化处理后，在室温和７００℃疲劳裂纹扩展的规律．分析了影响疲劳裂纹扩展速率ｄａ／ｄＮ的诸多因素，结合ＳＥＭ断口，裂纹扩展路径观察及ＴＩＭ分析结果进行了讨论，并用ＦＯＲＴＲＡＮ程序绘出各种实验条件下的△Ｋ－ｄａ／ｄＮ曲线．     

激光熔覆（WC＋SiC）／Ni基复合涂层中合金元素的分布

利用２ＫＷ的ＣＯ２激光器的１６Ｍｎ钢表面激光熔覆（ＷＣ＋ＳｉＣ）／Ｎｉ基复合涂层，经ＳＥＭ及ＥＤＸ能谱分析表明，基体与涂层呈良好的冶金结合。承着凝固过程的进行，γ－Ｎｉ固溶体的形貌由平面晶发展为树枝晶，且γ－Ｎｉ固沉吟体间合金元素的含量及平面晶的厚度均随机扫描的变化而变化。     

纤维C—内标技术对TN12M10合金的SHS反应过程

利用特殊的Ｃ－内标技术对ＴＮ１２Ｍ１０合金的ＳＨＳ反应结晶过程进行了实验研究，发现包裹Ｃ－粒的包覆熔体中含有杂质与合金元素，随着温度升高，Ｃａ，Ｓｉ，Ｆｅ，Ｎｉ的含量减少，直至消失，Ｔｉ，Ｍｏ含量则随之增加；ＢＦＴ最后流到就近的Ｔｉ（Ｍｏ）Ｃ晶粒上结晶。因之，作者提出了ＴＮ１２Ｍ１０合金ＳＨＳ反应结晶过程的顺序：（１）Ｃａ，Ｓｉ，Ｎｉ，Ｆｅ，Ｔｉ，Ｍｏ等杂质及合金元素随着加热温度铁升高，依次先后熔     

碳、铌对Inconel 718合金熔敷层组织与性能的影响

为了提高Inconel 718合金焊接接头的塑、韧性，开发了具有良好力学性能和热加工性能的镍基高温合金焊接材料.通过适当调整Inconel 718高温合金中的碳、铌含量，并在一定工艺参数下进行熔敷，然后再进行扩散退火和固溶、时效处理；研究了C、Nb含量变化对Inconel 718高温合金熔敷层的组织和性能的影响.实验结果表明：焊后熔敷层的组织主要由γ固溶体构成，枝晶间出现白色的Laves相；经扩散退火处理后，Laves相发生溶解；在相同的处理条件下，熔敷层的屈服强度和硬度对碳、铌成分的变化比较敏感.     

激光熔覆TiCp／Ni基自熔合金复合耐磨涂层的组织

在４５钢表面激光熔覆３０％ｖｏｌＴｉＣｐ－Ｎｉ基自熔合金复合耐磨涂层，其组织由ＴｉＣ颗粒，γ－Ｎｉ与Ｃｒ２３Ｃ６型碳化物的共晶及γ固溶体枝状初晶组成。因冷却速度的差异，在涂层的不同部位分别得到了典型的花瓣状和规则六边形ＴｉＣ颗粒。ＴｉＣ颗粒与γ－Ｎｉ基体有一定的取向关系。     

Ti-6Al-2Zr-15Ni合金固溶过程中Ti2Ni相的形貌变化

利用光镜、扫描电镜、透射电镜和X射线衍射术观察和分析了Ti-6Al-2Zr-15Ni合金在不同温度固溶处理后的显微组织．该合金的铸态组织由枝晶和枝晶间共晶组成,枝晶为Ti2Ni纤维和仅基体组成的共析组织,枝晶间共晶由棒状α相和Ti2Ni基体组成．固溶处理时Ti2Ni相的形貌和尺寸发生了明显变化．850℃以下固溶,随固溶温度的升高,纤维状的Ti2Ni发生了熔断,粒化和粗化等过程．900℃固溶时,枝晶内仪相转变为β相,Ti2Ni溶解,枝晶间α/Ti：Ni共晶组织转变为半连续Ti2Ni相分布于晶界．随温度的升高,晶界Ti2Ni球化,并在960℃时发生多边化,970℃时多边形Ti2Ni的棱角钝化．     

Semi-solid slurry preparation and rolling of 1Cr18Ni9Ti stainless steel

The preparation and rolling of the semi-solid slurry 1Cr18Ni9Ti stainless steel were researched. The experimental results show that when stirred for 2-3 min under the given test condition, the semi-solid slurry with about 50%-60% (volume fraction) solid and the spherical primary austenitic grains in the size of 100-200μm can be obtained, and it is easy to be discharged from the bottom little hole of the stirring chamber. The semi-solid slurry of 1Cr18Ni9Ti stainless steel can be rolled into the given plate successfully. However, the solid phase and liquid phase are easily separated in the rolling process, so that the solid primary austenitic grains are concentrated in the center and the liquid phase is near the edge of the rolled plate. The strengths of the plate rolled in the semi-solid state are higher than that of the traditionally repeated hot-rolled plate of 1Cr18Ni9Ti stainless steel.     

Effect of Various Carbides on the Wettability in Ni/Ti（C,N） System

The wettability in Ni / Ti （ C, N ） systems with various carbides additions was investigated by the sessile drop technique. The substrates prepared by HP at 2073 K for 1 h before and after wetting were characterized by XRD . The microstructure ca metall ceramics interfaces was observed via SEM in a back scattered mode. Furthermore , an X-ray energy-dispersive spectrometer （ EDS ） attached to SEM was used to study the element diffusion in interfacial regions. The resalts reveal that reactive wetting takes place in the system in high tempercature wetting procedure , which is controlled by diffusion and dissolution mechanism. Results also show that the contact angles decrease with various carbides additions, iuelnding WC , Mo2 C, TaC , NbC and VC , and decrease continuously with the increasing of additions. The order of the contact angles in Ni/Ti （ C, N ） systems with 10 wt% carbides acMitions is Mo2 C 〈 TaC 〈 WC 〈 VC 〈 NbC. The enhancement of the wettability is due to an alloying procedure during high temperature wetting when metallic atoms diffuse into Ni phase, which decreases the interfacial energy of Ni/ Ti （ C, N） systems.     

Interfacial reaction mechanism of TiBw/Ti6Al4V composites and Inconel 718 alloys by GTAW heat transmission

A good joint of Ti Bw/Ti6Al4V composites and Inconel 718 alloys was obtained by Gas Tungsten Arc Welding(GTAW) heat transmission. The interfacial reaction mechanism of joint was investigated and analyzed in details. Owing to the heat input applied on the surface of Ti Bw/Ti6Al4V composites, a solid-state reaction layer appeared at the interface of Ti Bw/Ti6Al4 V composites to Inconel 718 alloys. The thickness of the reaction layer was obviously increased with increasing heat input.Developing of reaction layer mainly depended on the diffusion of elements of Ti and Ni through the interface during welding to form solid solutions and intermetallic compounds(IMCs). The reaction layer can be divided into Ti-rich zone(layer 2) and Nirich zone(layer 1). In Ni-rich zone, relatively coarse dendrites were the predominant, however, more brittle IMCs like Ti2Ni were found in the Ti-rich zone. Micro hardness of reaction layer was much higher than that of base metal. While a slight decrease of hardness was found between Ti-rich zone and Ni-rich zone due to the formation of TiNi.     

Fabrication of in situ Ti2AlN/TiAl composites by reaction hot pressing and their properties

Ti2AIN/TiAI composites with different volume fractions of reinforcement were successfully fabricated by hot-pressing sintering method （reaction hot pressing） using Ti, Al and TiN powders as starting materials. The synthesis process includes four stages： first, the reactions between Al and Ti powers and between Al and TiN powders respectively occur and result in TiAl3 phase; secondly, AI powders in the sample are exhausted; the remaining Ti cores react with TiAl3 layer to form Ti-Al intermetallics; moreover, a few Ti2AlN particles precipitate from the TiAl3 phase; thirdly, Ti-Al intermetallics react with the remaining Ti cores to form Ti3Al and TiAl phases. TiAl phase and original TiN powers are in direct contact each other; finally, the residual TiN powers react with TiAl phase and result in a plenty of TizAIN phase. Compared with TiAl matrix, the hardness, elastic modulus and high-temperature compressive strength of Ti2AlN/TiAl composite are improved obviously and they are all enhanced with increasing the volume fraction of Ti2AlN phase.     

La(Ni,Sn)5+x (x=0～0.35)贮氢合金的晶体结构与电化学性能

系统研究了La(Ni,Sn)_5+x（x=0~0.35) 无Co贮氢合金的化学计量比对其晶体结构及电化学性能的影响.X射线衍射分析仪（XRD）分析表明，上述合金均为单相CaCu₅结构.但在过计量比(x>0)合金的结构中，有部分1a位置元素（La）的原子被沿c轴定向排列的Ni-Ni“哑铃”对所替代，且其替代La原子的分数随x的增大而增多，从而导致合金晶胞的c轴及c/a比值明显增大，晶胞体积有所减小，并显著降低了合金的吸氢体积膨胀率.电化学测试表明，增大x值可使合金的循环稳定性得到显著提高，但也使合金的最大放电容量和高倍率放电性能有所降低.研究发现，由于合金的化学计量比增大会使其结构中含有较多的Ni-Ni“哑铃”对，合金的抗吸氢粉化能力得到了明显的改善，从而使合金在充放电过程中的反应比表面积有所减小、腐蚀速率得到抑制、循环稳定性得到显著提高.但合金反应比表面积的减小也导致了电极反应的速率的减小，从而使其高倍率放电性能有所降低.     

Thermodynamic prediction of metastable phases of Ni-Ti system formed by ion beam mixing

By taking into account the valence electron number and periodic number of constituting metals, a new method is first proposed to calculate the structural enthalpy in the Miedema’s model and the modified Miedema’s model is then used to predict the formation of metastable phases in Ni-Ti system. To testify the relevance of the present prediction, the multilayered films of Ni1-xTix (x=27.3, 30.5, 42.4, 83.1, 89) are prepared and irradiated by 200 keV xenon ions. Experiment results reveal that uniform amorphous phases are obtained in the Ni72.7Ti27.3, Ni69.5Ti30.5, and Ni57.6Ti42.4 films by increasing the irradiation dose. While for the Ni16.9Ti83.1 and Ni11Ti89 films, an hcp Ti-based solid solution phase and a bcc Ti-rich solid solution phase coexist upon irradiation dose higher than 6×1014 Xe+/cm2. The predictions of relative stabilities of metastable phases in Ni-Ti system by the modified Miedema’s model match well with IBM experiments, thus justifying the modification proposed in the present study.     

原位自生TiC和（TiW）C增强Fe基复合材料的研究

利用块体原材料原位合成10vol%TiC-Fe和(TiW)C-Fe两种复合材料,采用扫描电镜分析了复合材料的微观结构,利用X射线分析了相组成。结果表明,在TiC-Fe复合材料中,TiC作为唯一的第二相呈现粒状和条状两种形态。分析认为,粒状相为亚共晶相,而条状第二相为共晶相。通过用W替代部分Ti,成功地制备了10vol%(TiW)C-Fe复合材料,其中,(TiW)C作为唯一的第二相比较均匀地分布在Fe基体中,其形态大部分呈粒状,条状相较少。在粒状(TiW)C相中,中心富Fe,而边缘W、Ti和C元素的分布是均匀的。与TiC相比,(TiW)C的密度与Fe更为接近,它更适合作为大型铸件的增强相。     

GRADIENT VARIATION OF COMPOSITION AND QUANTUM CHEMISTRY CALCULATION OF(Ti-Nb)C-Ni COMPOSITE

(Ti,Nb)C Ni composite is prepared.Theanalyses of SEM,EPMA and TEM/EDAX show that (Ti,Nb)C-Ni consists of three phases,which are called interior,transitional and Ni phases respectively.Several models arecalculated by self-consistent-field variational Xa(SCF-DV-Xa)me thod,one of the quantum chemistry calculatingmethods.The calculated results show that when Ni elementincreases,the bond orders(measures of strength of covalentbonding)of Ti-C and Ni-C in the models decrease corre-spondingly,which is to say that there is a gradient variation of the covalent bond in the transitional phase which is compat-ible with both the interior and Ni phases.It is beneficial for improving the mechanical properties of the materials.     

La_(0.7)Ca_(0.3)MnO_3与Al复合体系电磁输运性质的研究

研究了具有庞磁电阻(CMR)效应的锰基钙钛矿氧化物La0.7Ca0.3MnO3(LCMO)与Al复合体系的电磁输运性质.根据X射线衍射分析及电阻率与温度的关系可知,在(1-x)LCMO+xAl(x代表物质的量)复合样品中,发现了新相Al2O3,且LCMO晶格常数和晶胞体积随Al掺量的增加而减小,同时在复合样品中出现了除对应LCMO本征金属-绝缘体转变峰TP1之外,在较低温度区域出现了另外一个转变峰TP2的现象,且复合样品转变峰TP2比LCMO本征金属-绝缘体转变峰TP1处于较宽的温度区域.经研究认为,在合成复合样品的实验过程中,既有Al被氧化为Al3+替代Mn3+的替代反应,也有Al经过高温与空气发生反应生成Al2O3,进而填隙在LCMO晶界处影响母体的电磁输运性质.本系列复合物中较宽温度区域CMR的发现为今后同类问题的研究提供了很好的实验基础.