激光熔覆TiC／Ni＋Cr涂层过程中陶瓷相的行为

借助ＳＥＭ、ＴＥＭ对激光熔覆ＴｉＣ／Ｎｉ＋Ｃｒ过程中陶瓷相ＴｉＣ的行为进行了研究。结果表明：未受基体中Ｆｅ扩散影响的熔覆层表层，ＴｉＣ仍保持为完整的六边形截面颗粒。交互扩散区的ＴｉＣ颗粒在凝固应力作用下可能产生裂纹。溶解促进裂纹的萌生和扩展。溶解后的陶瓷相与粘结相交互作用生成（Ｆｅ，Ｃｒ）２３Ｃ６。溶解后的陶瓷相在凝固过程中重新析出，析出的陶瓷相可使涂层强化。     

Fe3Al—Ti超塑性变形过程中晶粒形态演化规律

对Ｆｅ３Ａｌ－Ｔｉ合金超塑性变形中不同应变量下的晶粒形态进行了研究，发现Ｆｅ３Ａｌ－Ｔｉ行为与连续再结晶有关，随变形量增大，晶粒逐渐细化，但晶粒形状变化不大，并沿拉伸方向有所伸长。ＴＥＭ分析表明，晶粒细化过程与超塑性过程中亚晶界向大角晶界的演化有关。本文对Ｆｅ２Ａｌ－Ｔｉ合金超塑性变形机理进行了初步的探讨。     

Fe_3Al－Ti超塑性变形过程中晶粒形态演化规律

对Ｆｅ_３Ａｌ－Ｔｉ合金超塑性变形中不同应变量下的晶粒形态进行了研究。发现Ｆｅ_３Ａｌ－Ｔｉ超塑性行为与连续再结晶有关，随变形量增大，晶粒逐渐细化，但晶粒形状变化不大，并沿拉伸方向有所伸长。ＴＥＭ分析表明，晶粒细化过程与超塑性过程中亚晶界向大角晶界的演化有关。本文对Ｆｅ３Ａｌ－Ｔｉ合会超塑性变形机理进行了初步的探讨。     

Ti—Fe机械合金化中氢致非晶化的研究

研究了氢原子对Ｔｉ－Ｆｅ系机械合金化的影响,应用 ＸＲＤ,ＤＳＣ,ＴＥＭ等方法测试了Ｔｉ－Ｆｅ系和Ｔｉ－Ｆｅ－ＴｉＨ２系的机械合金化反应过程和产物结构的特征。研究结果表明,氢原子在机械合金化过程中诱导非晶ＴｉＦｅ相的形成,由于氢原子的影响,非晶ＴｉＦｅ相的结构弛豫温度和晶化温度低于机械合金化得到的非晶ＴｉＦｅ相相应的温度。     

铸渗法制造双金属耐磨复合材料

阐述了铸渗工艺及方法。同时采用载体法铸渗Ｃｒ－Ｆｅ、Ｍｏ－Ｆｅ和Ｔｉ－Ｆｅ等铁合金来提高球铁铸件表面的耐磨性。试验结果表明,球铁铸件铸渗后,表面形成一层约４ｍｍ厚的合金白口铁强化层,经磨粒磨损试验证实,该表层的耐磨性是球铁耐磨性的２．０１倍。     

铜镍合金海水腐蚀的表面与界面特征研究

采用金相（ＯＭ）、俄歇（ＡＥＳ）、扫描电镜（ＳＥＭ）及透射电镜（ＴＥＭ）等技 术手段对实海暴露试样进行探测分析,揭示了表面膜缺陷（如碳膜）、晶界缺陷（晶界析出物）等加速该 合金腐蚀进程的试验现象和内在根据,特别指出影响该合金海水腐蚀产物膜稳定性的主要因素,分析了其中的沿晶扩散及应变诱生调峰分解与沿晶腐蚀、沿晶脆断的相互关系。     

硼在12Cr2MoWVTiB钢高压锅炉管热制管及服役过程中的变迁

用α－粒子径迹显微照相技术，并行电子能量损失谱（ＰＥＥＬＳ）分析电镜技术和金相试验方法，研究了１２Ｃｒ２ＭｏＷＶＴｉＢ（１０２）钢铸态、开坯态（锻造、初轧后）、轧管态（穿孔、连轧、张减后）、热处理态（正火、回火后）及服役态（蠕变、持久试验后）硼元素的存在形式和分布规律。研究表明，铸态（本样为例）硼元素随机分布：晶内固溶，轻度晶界富集。经锻造或初轧开坯后，硼的分布渐趋均匀。穿孔、张减等重复热加工过程使硼出现晶界的偏聚迹象：正火使晶界硼元素明显偏聚，同时伴随Ｃｒ的富集。正火加回火使硼大量向晶界迁移并形成富Ｃｒ的Ｍ_（２３）（Ｂ，Ｃ）_６，其后的服役状态（蠕变或持久试验），含硼的Ｍ_（２３）（ＢＣ）_６碳化物重新溶解而使硼回到晶粒内部并逐步均匀化。研究指出，硼的晶界析出与富Ｃｒ的Ｍ_（２３）（Ｂ，Ｃ）_６相有密切关系，即当（Ｆｅ，Ｃｒ）_（２３）Ｃ_６存在于晶界时，易形成（Ｆｅ，Ｃｒ）_（２３）（Ｃ，Ｂ）_６型碳化物析出（硼相）。１０２钢中硼含量和铬含量及热处理工艺是影响硼元素迁移行为的两大主导因素。     

TA2／A3爆炸复合界面的扩散反应

借助于ＯＭ，ＳＥＭ，ＴＥＭ及ＡＥＳ和ＸＲＤ等测试技术和手段，系统地研究和深入探讨了钛（ＴＡ２）／钢（Ａ３）爆炸复合界面扩散反应区内的微观组织结构、反应相的形成和生长规律，结果表明：经１１７３Ｋ以下（即ＴＡ２的β转变温度以下）热处理，在ＴＡ２侧界面形成ＴｉＣ，它阻碍Ｆｅ和Ｔｉ互扩散，不能生成Ｆｅ_（２）Ｔｉ，ＦｅＴｉ．经１２２３Ｋ以上（即在ＴＡ２的β转变温度以上）热处理，沿界面生成按抛物线规律长大的层状金属间化合物（Ｆｅ２Ｔｉ，ＦｅＴｉ）；并由于Ｆｅ的扩散，在ＴＡ２侧Ｆｅ的含量高处形成β－Ｔｉ或β－Ｔｉ＋α－Ｔｉ组织，而在Ｆｅ含量低处形成马氏体转变产物，此外，β转变层也按抛物线规律生长．     

海水腐蚀导致铜镍合金的沿晶析出

半硬态B_(Fe30-1-1)铜镍合金管材在实海暴露过程中随着表面氧化膜的腐蚀脱落,在晶界上出现沿晶析出物,形成较大的沿晶腐蚀倾向。TEM观察表明,这种析出物是调幅分解(Spinodaldecomposition)的产物,其衍衬象为明暗相间的条纹,调幅波长小于50nm。该析出物使材料在拉伸时出现脆性沿晶断口,强度略有上升,但大大恶化了材料的耐海水腐蚀性能。文中根据试验结果阐明了析出物的生成动力,认为是海水腐蚀导致材料的应力状态改变(即应变诱生)及合金元素沿晶界向表层的扩散促使已形核的析出物粗化所致。     

Fe—Cr—Al合金的碳化物析出脆化及钇对脆性的影响

通过力学性能测定，ＳＥＭ和ＴＥＭ分析发现，碳化物在α相晶界析出降低晶界结合强度，使Ｆｅ－（１５－２５）Ｃｒ－（４－５）Ａｌ合金严重脆化。在４７５℃时效时，此过程在１００－３００ｈ前起主导作用，时效时间超过１００－３００ｈ后，从α相均匀析出α‘相的作用增强两个阶段的脆化特征不同。     

工业纯Al的缝隙腐蚀再钝化电位

工业纯Ａｌ的缝隙腐蚀再钝化电位ＥＲ是缝隙结构的特征值，与缝隙腐蚀下限电位ＶＣＲＥＶ一致，比孔蚀电位负约１００ｍＶ，说明缝隙腐蚀更易发生．     

氯化物溶液中敏化304不锈钢应力腐蚀开裂的临界电位

研究了氯化物浓度、溶液温度、应力及敏化程度对敏化304不锈钢在NaCI水溶液中晶间型应力腐蚀开裂的影响。结果表明，材料的敏化程度、NaCI浓度、溶液温度和应力对敏化304不锈钢的ER.SCC有显著的影响，敏化304不锈钢的DR．SCC低于ER．CREV，应力腐蚀开裂发生在正于ER．SCC的电位范围，而电位低于该值则免于发生应力腐蚀开裂，由此得知，ER．SCC可适用于评价敏化不锈钢的应力腐蚀开裂敏感性。     

Behaviour of crevice corrosion in iron

Crevice corrosion was investigated in iron exposed to a strong-buffered acetate solution (0.5 M CH₃COOH + 0.5 M NaC₂H₃O₂), pH = 4.66. The current and the potential gradient within the crevice were measured at crevice depth (L) = 7.35, 8, 10, and 15 mm, for a crevice that was positioned facing the electrolyte in a downward position. A remarkable shift in potential (>1.2 V) in the active direction was measured inside the crevice cavity, when the potential at the outer surface was held at 800 mV(SCE). Experimentation showed that there is a critical depth value, above which little changes occur on the transition boundary between passive and active regions on the crevice wall, x_pass, and below which x_pass location shifts sharply towards the crevice bottom. Steeping of the potential gradient occurred with time indicating enhancement of crevice corrosion, which was seen by the gradual increase in the current. These findings were in close agreement with the IR voltage theory and related mathematical model predictions. Morphological examination showed an intergranular attack around the active/passive boundary (x_pass) on the crevice wall.     

Crevice corrosion monitoring of titanium and its alloys using microelectrodes

Crevice corrosion of titanium and its alloys in 10% sodium chloride was investigated at 100°C with the aid of microelectrodes. Potential, pH and chloride ion concentration inside the crevice were monitored using an Ag/AgCl electrode, a tungsten microelectrode and a Ag/AgCl chloride ion selective microelectrode, respectively. The pH and Cl^? concentrations within the crevice were calculated from the standard potential‐pH and potential‐log[Cl^?] calibration curves. The effect of Mo on the crevice corrosion of titanium was also studied. The passivation behavior on the titanium and Ti‐15%Mo alloy was studied using electrochemical impedance studies. There was no apparent change in pH and Cl^? ion activity inside the crevice for the alloy at 100°C, whereas a marginal decrease in pH and increase in Cl^? ion concentration were observed for pure titanium. Thus pure titanium is susceptible to crevice corrosion in hot 10% NaCl solutions at 100°C. The chloride ion activity was found to be reduced for the alloy so that the pH inside the crevice increased. The corrosion reaction resistance (R_t) was found to increase with the addition of Mo as an alloying element. It also increases with externally applied anodic potential. Hence, Mo is an effective alloying element, which enhances the crevice corrosion resistance of titanium.     

油气开采用钛合金石油管材料耐腐蚀性能研究

选取5种油气开发常用钛合金材料(Ti-6Al-4V、Ti-6Al-4V-0.1Ru、Ti-6Al-2Sn-4Zr-6Mo、Ti-3Al-8V-6Cr-4Zr-4Mo和Ti-5.5Al-4.5V-2Zr-1Mo)为研究对象,使用高温高压釜模拟国内典型严酷服役工况环境,研究了不同钛合金材料耐均匀腐蚀、局部腐蚀、点蚀、应力腐蚀开裂(SCC)及缝隙腐蚀的性能,通过使用扫描电镜和能谱分析等手段对腐蚀形貌和腐蚀产物进行了分析,并使用电化学方法对不同合金的耐腐蚀机理进行了研究。结果显示,在所测试工况条件下,所有钛合金材料腐蚀反应均为阳极控制过程,均匀腐蚀速率均低于0.001mm/a,并且对应力腐蚀开裂均有良好的抗力。Ti-6Al-4V和Ti-5.5Al-4.5V-2Zr-1Mo合金出现明显的点蚀和缝隙腐蚀问题。对腐蚀机理研究表明,在工况条件温度下,随着pH值的降低,所有钛合金均发生自腐蚀电位降低,极化电阻减小,腐蚀电流增大,耐腐蚀性能下降,其中Ti-6Al-4V耐腐蚀性能下降的最为明显,研究结果为油气开发工况下钛合金石油管的选材和缝隙腐蚀问题防治提供理论基础。     

W0714己内酰胺薄膜蒸发器下料管管壁腐蚀减薄失效分析

用化学方法、金相显微镜和扫描电镜等对腐蚀减薄失效后的W0714己内酰胺薄膜蒸发器下料管管壁进行了分析,结果表明:此设备用304L不锈钢管壁在非氧化性介质中发生了非敏化态的晶间腐蚀,其腐蚀失效的原因是过钝化电位范围内的电化学溶解所致。     

Electrochemical behaviour of commercially pure titanium and Co—Cr alloy in Ringer‘s solution

The electrochemical behaviors of commercially pure titanium(CP Ti) and Co-Cr alloy in Ringer‘s solution have been investigated.The results indicate that the electric potential of passive region for CP Ti is up to 3000mV,and its passive current density is 3.078 μA/cm^2,The excellent corrosion resistance of CP Ti can be attributed to the formation of TiO2 oxide film.The passive region of Co-Cr alloy is 770mV,which is narrower than that of CP Ti.However,no hystersis loops are found in the reverse scanning curves of Cu-Cr alloy.A complex oxide film of Co3O4,Co2O3,and Cr2O3 formed on the surface provides Co-Cr alloy with a stable electrochemistry property.The corrosion rates of the crevice samples increase with the pH value of medium decreasing.The electron probe microanalyzer(EPMA) analysis indicates that Ti in CP Ti and Co,Cr in Co-Cr alloy dissolve in crevice area due to the Sealed-Cell effect.     

Localized corrosion of alloy 22 in the potential Yucca Mountain repository environment

The U.S. Department of Energy (DOE) has indicated that it may use Alloy 22 as the waste package outer container material for the potential high-level waste repository at Yucca Mountain, Nevada. Additionally, a drip shield, made of titanium grade 7 and titanium grade 29, may extend the length of the emplacement drifts to enclose the top and sides of the emplaced waste package. Localized corrosion in the form of crevice corrosion could be one degradation process that may adversely affect the waste package performance. This paper will summarize the work conducted to evaluate the effects of environmental conditions relevant to the potential Yucca Mountain repository, metallurgical states (e.g., mill-annealed and welded plus solution annealed), and similar and dissimilar metal crevices on the crevice corrosion susceptibility of Alloy 22. This work also evaluates crevice corrosion propagation behavior resulting from contact with Alloy 22 or titanium grade 7.     

镍对304不锈钢在NaCl溶液中缝隙腐蚀行为的影响

采用化学浸泡实验和电化学测试技术,探讨了Ｎｉ元素对３０４不锈钢在０．３％ＮａＣｌ 溶液中缝隙腐蚀行为的影响。结果表明,合金元素Ｎｉ的加入,可提高ＥＲ,抑制不锈钢的活性溶解行为 和有效提高抗缝隙腐蚀能力。     

316L不锈钢法兰腐蚀失效分析与对策

对316L不锈钢法兰在苯甲酸环境中因腐蚀失效进行了分析，发现不锈钢因焊接导致的晶间腐蚀是不锈钢法兰腐蚀失效的主要原因，此外，焊接材料与基体材料的不同以及使用了导电的垫片石墨会引起电偶腐蚀，不锈钢法兰之间存在缝隙会引发缝隙腐蚀，提出了解决措施．