海水管道焊缝下游区是发生腐蚀的热点区域.为探究B30管道焊缝余高对与其下游区腐蚀行为的影响,利用原位电化学测试装置和自制循环海水冲刷装置,在3天、7天、15天、30天4个冲刷节点进行试验.测试了3种模拟焊缝余高(0 mm;0.5 mm;1.5 mm)在紧邻热影响区和下游30 mm处母材区的电化学阻抗谱,用扫描电镜观察了试样表面的腐蚀形貌,结合COMSOL软件建立了有限元仿真流态模型,探讨了余高对介质流态的影响.结果表明,在有焊缝情况下,热影响区和母材区阻抗值均小于无焊缝结构,焊缝结构会加速下游区的腐蚀,且余高越大,腐蚀倾向也越大;热影响区腐蚀速率均大于母材区;流态模型显示出在热影响区位置出现了涡流,涡流加速了热影响区的腐蚀.

目的 基于典型污损释放型防污涂层浅海挂板试验,考察涂层防污性能得分及关键防污特性参数随浸海时间的变化规律,构建污损释放型防污涂层服役寿命模型,并推算关键防污特性参数的失效临界值,以此为评价依据,建立防污涂层室内加速评价方法.方法 依据GB/T 5370-2007《防污漆样板浅海浸泡试验方法》进行浅海挂板试验,收集青岛、厦门、三亚3个海域涂层的表面能、粗糙度、硬度、Si—CH3/Si—O—Si比值以及防污性能得分等各项性能数据.通过数学分析确立涂层防污性能得分与关键防污特性参数之间的关系,并计算涂层失效时各参数的临界值.设计室内加速老化试验,对比室内加速老化试验与浅海挂板试验中涂层各项性能的变化趋势,分析两者间的相关性.借助X射线光电子能谱和傅里叶红外光谱研究涂层的失效机制.结果 及结论结果表明,室内加速老化试验数据与浅海挂板试验数据具有较好的相关性.基于涂层的表面能、粗糙度、Si—CH3/Si—O—Si比值测试可以得出,室内加速老化1 h相当于实海浸泡0.1 a的水平.涂层失效主要是由于组成涂层主体的有机硅Si—O—Si主链发生降解,侧链的C—H也被氧化断裂,生成了亲水性的—OH等基团,并在表面形成了无机硅氧化物.

有机硅污损释放型防污涂层(FRC)具有对环境友好和长效防污的优势,目前在船舶水下防污中已有大量应用,具有广阔的应用前景.船舶防腐底漆通常为环氧体系,直接在底漆表面涂覆FRC,易因环氧底漆与FRC相容性差、连接能力弱而脱落失效.因而,在环氧底漆和有机硅污损释放防污面漆之间涂覆中间连接漆显得十分必要.基于通用环氧防腐底漆、FRC表面能和表面残余活性基团分析,试验设计制备了有机硅环氧配套连接漆,通过添加表面浸润剂改善了连接漆与底漆和面漆的浸润性,增强了连接漆的连接性能.涂料颜基比对连接漆与底漆附着性能影响较大,附着强度随着颜基比升高而逐步提高,处于4.5～12 MPa之间;对连接漆与面漆附着性能影响较小,基本在1.4 MPa左右,均为内聚破坏;有机硅环氧连接漆与面漆、底漆之间存在化学键合作用.与IP1100SR配套涂层对比显示,自研配套涂层在螺旋桨叶梢部位漆膜脱落情况较之弱得多,具有更好的海洋环境适应性.

通过显微组织观察、拉伸测试、表面硬度测试及浸泡试验,研究不同焊接参数对7B04铝合金搅拌摩擦焊接头组织与性能的影响.结果表明:焊接接头的金相组织可分4个区域,为焊核区、热力影响区、热影响区和母材区.焊核区的晶粒呈等轴状,约为5μm;热力影响区晶粒呈条弧状,晶粒间分布着细小等轴晶;热影响区晶粒形态与母材区相似,呈板条状.母材区表面硬度最高,从母材区到热力影响区逐渐降低;热力影响区到焊核区硬度略微上升,但焊核区的表面硬度低于热影响区.7B04铝合金搅拌摩擦焊在转速一定下,焊接速度越快,接头抗拉强度越低,韧性越差.搅拌摩擦焊接头不同区域的耐蚀性能存在差别,母材区和热影响区耐蚀性能相对较好,焊核区次之,热力影响区耐蚀性能最差;在转速一定下,焊接速度对焊接头耐蚀性能的影响有限,但焊接速度较慢时,接头的耐蚀性能相对较好.

目的 研究揭示低温对结构钢冲击韧性和拉伸性能的影响规律.方法 采用实验室冲击试验和拉伸试验,研究–70～20℃内3种钢材的冲击吸收能量以及抗拉强度、断后伸长率等力学性能的变化规律.利用金相显微镜(OM)和环境扫描电镜(SEM)观察和表征材料的显微组织及冲击断口形貌特征,并采用冲击吸收能量法测定材料的韧脆转变温度.结果 45A和300M具有体心立方晶格,随着试验温度的降低,45A冲击吸收能量变化规律整体呈S形,发生韧脆转变现象,300M冲击吸收能量下降幅度明显低于45A,–70℃时的冲击吸收能量保持率仍高达75％.1Cr18Ni9具有面心立方晶格,在试验温度范围内,冲击吸收能量变化平缓,未发现韧脆转变倾向.随着温度的降低,3种钢材的抗拉强度、屈服强度均不同程度地增高,而断后伸长率和断面收缩率随温度的降低而减小.结论 钢的低温脆性与晶格类型有关,体心立方晶格的金属具有冷脆性,而面心立方晶格金属通常不具有冷脆倾向.由冲击吸收能量法测得45A的韧脆转变温度为–28℃,300M的韧脆转变温度<–70℃.

目的 研究湿热海洋、干热沙漠、寒冷乡村、暖温高原四种典型大气环境对7B50铝合金腐蚀行为的影响.方法 采用户外大气自然环境暴露试验,通过宏观腐蚀形貌分析、金相显微形貌分析、腐蚀深度分析和拉伸性能分析,对比研究7B50-T7751和7B50-T77511两种铝合金在不同大气环境中的腐蚀行为和规律.结果 暴露试验周期为3 a时,7B50-T7751铝合金在湿热海洋大气环境中腐蚀严重,局部最大腐蚀深度为166μm,抗拉强度和断后伸长率分别下降了5％和25％;在干热沙漠大气环境下腐蚀较重,局部最大腐蚀深度为44μm;在寒冷乡村、暖温高原大气环境下未见明显腐蚀.7B50-T77511铝合金在四种典型大气环境下均表现出明显腐蚀,局部最大腐蚀深度分别为141、80、42、29μm.结论 两种7B50铝合金在典型大气环境中表现出不同的耐蚀性,在微观上均表现为点蚀和晶间腐蚀的混合腐蚀,具有明显的晶间腐蚀和剥蚀倾向.两种铝合金暴露在相同大气环境中时,7B50-T7751板材耐蚀性较7B50-T77511型材略好.

目的 对比研究铜合金、紫铜在我国黄海、东海和南海海域具有代表性的港口海水环境中的污损、腐蚀行为.方法 依据GB 12763.6—2007《海洋调查规范》和GB/T 5776—2005《金属和合金的腐蚀试验方法》,通过实海挂片研究ZQMnD12-8-3-2、铜镍合金B10/B30和紫铜T2在我国典型海域青岛港口、舟山港口、三亚港口的生物污损与腐蚀状况.结果 铜镍合金B10、B30和紫铜T2在三海域均具有良好的抑制污损生物附着的性能,其中紫铜抑制污损生物附着的性能最为突出,但其腐蚀严重,腐蚀速率为3.97×10–2～8.48×10–2 mm/a;铸造青铜ZQMnD12-8-3-2虽然含铜量略高于铜镍合金B30,但由于其腐蚀产物易附着于材料表面,其污损抑制性能较差.结论 铜镍合金B10、B30和紫铜T2均有抑制污损生物附着的性能,但受不同海域环境因素和材料表面腐蚀产物致密性的影响有所差异.受泥沙水质影响,舟山港口内铜合金的腐蚀速率较高,腐蚀显著,三亚港口内紫铜的腐蚀速率最高.

目的 研究湿热海洋、干热沙漠两种典型大气环境对7A85铝合金腐蚀行为的影响.方法 在万宁、敦煌两种典型环境中开展7A85铝合金大气暴露试验,利用金相显微镜分析7A85铝合金在我国两种典型大气环境中的腐蚀特征,定期测试该材料的拉伸强度和腐蚀深度.结果 暴露3 a,7A85铝合金湿热海洋、干热沙漠两种典型大气环境中的最大腐蚀深度分别为254、90μm,抗拉强度分别下降了18％和5％,断后伸长率分别下降了72％和22％.结论 7A85铝合金暴露于相对湿度较低的干热沙漠环境,表面形成的腐蚀产物膜会阻止腐蚀的进一步发生;暴露于湿热海洋大气环境,随暴露时间的延长,7A85铝合金腐蚀逐渐加深.

目的 揭示自然环境和疲劳交替作用下,2024典型连接结构环境损伤规律与损伤机制.方法 采用静态暴露试验和静态暴露-疲劳交互试验,对比研究2024典型连接结构的累积损伤特性和疲劳寿命退化规律.通过电液伺服材料试验机测试不同试验周期的试样疲劳寿命,利用环境扫描电镜(SEM)和金相显微镜(OM)观察和表征试样疲劳断口形貌及微观腐蚀特征,利用X射线应力分析仪测量了周期加载引起的孔边残余应力变化.结果 金相分析结果表明,周期疲劳加载对2024连接结构的腐蚀损伤进程有一定加速性,交互试验2年的腐蚀深度(51.9μm)大于静态暴露试样(47.0μm).中值疲劳寿命变化曲线显示,相同环境腐蚀条件下,静态暴露的试样疲劳寿命较"疲劳+静态暴露"交互试验方式有所提高,裸材试样的中值疲劳寿命约为交互试验的1.5～2.3倍,带涂层试样的中值疲劳寿命约为交互试验的1.1～1.4倍.紧固孔周边残余应力检测数据表明,受外加交变应力和环境腐蚀的叠加作用,孔边残余压应力逐渐减小,产生局部塑性变形,这会对疲劳寿命造成不利影响.结论 "疲劳+静态暴露"交互试验条件下的试样疲劳寿命退化与低载锻炼效应和电化学效应相互竞争、孔边残余压应力变化及微动磨损密切相关,从而呈现出先升高、后小幅振荡下降的趋势.

目的 针对铝合金结构展开腐蚀预测方法 研究,为飞机铝合金结构腐蚀损伤经济修理提供支撑.方法采用基于对数正态分布的统计学方法,开展飞机铝合金结构服役环境下的腐蚀损伤分布规律研究,并在此基础上进一步开展基于概率的腐蚀损伤预测方法.结果 使用对数正态分布对腐蚀损伤分布进行描述是可行的,基于对数正态分布的概率腐蚀损伤预测方法在不同可靠度下精度有所差异.结论 基于对数正态分布所建的腐蚀损伤预测模型可以实现对腐蚀损伤的预测.服役环境下,飞机铝合金结构腐蚀深度、体积及面积的扩展速率随时间的增长逐渐减缓.

针对金属结构在腐蚀环境、力学载荷等因素耦合作用下的损伤问题,简要介绍了金属结构环境损伤的主要影响因素,对当前国内外金属结构累积损伤理论与模型进行了系统梳理,重点探讨了金属结构环境累积损伤研究未来发展方向.通过多层级"积木式"研究建立环境(腐蚀)损伤参量-力学性能退化关联模型,是解决金属结构环境-载荷耦合作用下损伤演变规律与机理、剩余强度/寿命评价与预测等关键问题的有效路径.

Objective To provide useful references for the expansion of applications for TC18 titanium alloy as well as design and selection of product structure. Methods Atmospheric corrosion behaviors of TC18 titanium alloy in marine atmosphere environments for 6 years were investigated in virtue of the macro-micro corrosion morphology, static me-chanical property, fracture toughness and fatigue crack growth rate. Results In microscopic, there was no visible corro-sion as pitting. The tensile strength and fracture toughness decreased with the increase of marine atmosphere environment test time. The fracture toughness decreased by 6.7% after 4 years of test. The fracture morphology was quasi-cleavage;fatigue crack growth rate data and stress intensity factor range presented high linear relationship under da/dN-ΔK log-log plot for three test cycles of 2, 4 and 6 years. The parameters of Paris law da/dN=C(ΔK)nwere C1=5.846×10-11, n1=2.320, C2=6.01×10-14,n2=3.48,C3=1.81×10-13,n3=3.30.Conclusion TC18 titanium alloy exhibits low corrosion susceptibility in marine atmosphere environment.

目的 研究18CrNi4WA钢渗碳针阀体开裂失效原因.方法 通过化学成分分析、断口扫描分析、金相组织分析、能谱分析等测试手段,对18CrNi4WA钢渗碳针阀体的断裂模式及失效原因进行分析.结果 针阀体失效件原始材料符合针阀体制造要求,但渗碳淬火温度过高,未得到最优的渗碳层组织,燃油中存在的硫元素导致喷油孔位置产生严重腐蚀,燃油局部压力的变化导致针阀体表面产生空蚀损伤,裂纹起始于喷油孔圆周面,自裂纹源向外发散呈月牙状,为典型疲劳断裂特征.结论 腐蚀与空蚀损伤的协同作用加快裂纹的萌生,使针阀体在热疲劳及机械振动等交变载荷的作用下产生疲劳开裂,使用寿命大为降低.

Objective To evaluate the aging degree of protective coating comprehensively from mechanical property and appearance rating.Methods Nine coating degradation indexes of loss of gloss, color change, pulverization, foaming, mildew, rust, peeling, cracking, adhesion were selected to calculate and analyze the weight with the entropy value method. Results The comprehensive evaluation values of two kinds of protective coatings of TB06-9 + TS70-60 and TB06-9 + TS96-71 after marine atmospheric outdoor environment exposure for 5 years by the entropy method were 3.88. The an-ti-aging performance of the two protective coatings was almost the same.Conclusion The coating degradation index weight of loss of gloss, color change, pulverization, foaming, mildew, rust, peeling, cracking, adhesion was effectively identified by the entropy method, which provides an objective, real, effective and scientific evaluation method for multi index comprehensive evaluation of protective coating aging.

The current research status of stress corrosion theories were summarized, of which the hydrogen-induced cracking theory and anodic dissolution theory could better explain the stress corrosion cracking behavior of high-strength aluminum. According to the three necessary conditions for occurrence of stress corrosion cracking, the influencing mechanism of the metallurgy factors, environmental factors and stress factors on the susceptibility of stress corrosion cracking of high-strength aluminum alloy and the action results were discussed. Meanwhile, the research progress of laboratory simulation acceleration and natural environmental stress corrosion testing methods, existing problems and future research priorities were introduced.

Objective To investigate the influence of southeastern coastal atmospheric environment, which was hot, humid, salty, with high radiation, on the aging behavior of polyurethane coating. Methods Marine atmospheric exposure test of polyurethane coating was carried out in Wanning, Hainan. The aging characteristics and causes were analyzed from the appearance rating, gloss, color, adhesion, and infrared spectra. Results The coating resin fractured and main functional groups disappeared after marine atmospheric exposure test of polyurethane coating for four years. Conclusion Photodegradation by ultraviolet radiation together with degradation by water in marine atmosphere caused macroscopic and microscopic defects of the coating such as loss of light, color, pulverization and decrease of adhesion.

ABSTRACT:Objective To investigate the influence of four typical atmospheric environments including marine atmosphere, dry-heat desert, low temperature and low barometric pressure in high altitude on the corrosion behavior of 7050 high-strength aluminum alloy. Methods Atmospheric exposure test of 7050 high-strength aluminum alloy was carried out four typical environments in Wanning, Dunhuang, Mohe and Lhasa. The corrosion rule and behavior of 7050 high-strength aluminum alloy in four typical atmospheric environments in China were investigated by corrosion weight loss, mechanical property, corrosion morphology and metallurgical microscope. Results After 1-year Exposure, marine atmosphere had a significant effect on the corrosion weight loss, mechanical property, corrosion morphology and metallographic microstructure of 7050 high-strength aluminum alloy. Dry-heat desert environment had an effect on thecorrosion morphology and metallographic microstructure of 7050 high-strength aluminum alloy. And 7050 high-strength aluminum alloy was not sensitive to the corrosion of atmospheric environments of low temperature and low barometric pressure in high altitude. Conclusion The result showed that the impact of the four typical environments on the corrosion of 7050 high-strength aluminum alloy was in the order of Wanning>Dunhuang>Mohe and Lhasa.

The paper expounds the flow, basis, and principle of natural environmental test tailoring, discusses test environment, test method, test process, test condition, and test sequence of tailoring technology, as well as proposes the main points of the corresponding relevant tailoring.

To achieve the scientific management and efficient utilization of light material corrosion data ,the assessment , standardization and classification of corrosion data are carried on ,data structure design is based on the Oracle ,and the nine types of light materials corrosion data are archived and warehoused .A Corrosion data application system with lean structure and high availability is developed ,mainly based on J2EE platform and combined with Struts ,Spring and Hibernate frame-work techniques ,which can provide users with a variety of consulting services via Web to shared materials corrosion test re-sults for integrating a variety of functions such as data storage ,management ,query ,corrosion prediction and protection sys-tem recommend .

The effect of marine environment on fracture toughness for TA15 titanium alloy was studied by marine platform outdoor exposure test and marine splashing test.The results show that the fracture toughness for TA15 titanium alloy decreases with increasing marine atmosphere environment test time.The effect of marine splashing test for fracture toughness is bigger than marine platform outdoor exposure test.The fracture toughness of TA15 decreases 10.4% after 4 year's marine splashing test,the embrittlement increases by fracture morphology analysis.The near surface effects were discussed by XPS,most likely to be the diffusion of oxygen into the alloy.