材料期刊网

ATMOSPHERIC CORROSION OF 304AND 316 STAINLESS STEELS

J.S.Lu 1) , I.Odneval 2) and C.Leygraf 2) 1) College of Chemical Engineering , Zhejiang University of Technology , Hangzhou 310032 , China 2) Department of Material Science and Engineering , Royal Institute of Technology , Stockholm , 100 44 , Sweden

金属学报(英文版)

Atmospheric corrosion of 304 and 316 stainless steels was studied by field exposure test, in which rain water was collected and analyzed by atomic absorption spectroscope (AAS). Emphasis was put on the dissolution of chromium and nickel from the stainless steels by atmospheric corrosion and rain runoff. AAS analyses shows that the amounts of yearly chromium and nickel dissolution were less than 150ng/cm 2 and 50ng/cm 2 respectively for both 304 and 316 stainless steels. XPS analysis reveals the marked Cr enrichment on the 316 stainless steel after one year field exposure. SEM shows the morphology of corrosion pits on the steel surfaces.

关键词: atmospheric corrosion , null , null , null

Effect of deformation on the stress-induced martensitic transformation in (Ni47Ti44)(100-x)Nb-x shape memory alloys with wide hysteresis

Metals and Materials International

Martensite in TiNi-based alloys is reported to be thermally stabilized after a moderate deformation. Hence, this paper investigates the effect of deformation via stress-induced martensitic transformation on the reverse transformation behavior of (Ni47Ti44)(100-x)Nbx (x = 3, 9, 15, 20, 30 at.%) alloys. The stress-induced martensite appears to be stabilized in relation to the thermal-induced martensite that forms on cooling. This observation is confirmed by an increase in the reverse transformation start temperature, during which time the transformation temperature hysteresis reaches about 200 degrees C. Moreover, the Nb content in Ni-Ti-Nb alloy has a great influence on the transformation temperature hysteresis of stress-induced martensite as well as on the process of stress-induced mattensitic transformation. The mechanism of wide transformation temperature hysteresis is explained in terms of the microscopic structure of (Ni47Ti44)(100-x)Nb-x alloys. Furthermore, the temperature interval of the reverse transformation of stress-induced martensite was found to increase slightly as the strain of the high Nb-content alloy increased, though the value was much smaller than that of the thermally induced martensite. Finally, the paper explains the relation between this unique phenomenon and the elastic strain energy.

关键词: Ni-Ti-Nb ternary alloy;shape memory alloy;stress-induced martensitic;transformation;wide hysteresis;differential scanning calorimetry;ti-ni alloys;pseudoelasticity;thermodynamics;behavior

Prediction and improvement of mechanical properties of corrosion resistant superalloy K44 with adjusting minor additions C, B and Hf

Materials Transactions

The neural network (NN) method is applied to predict the influence of minor additions C, B and Won mechanical properties of cast superalloy K44 with heat treatment parameters considered. Furthermore, the influence of minor additions C B and Hf on phase stability is estimated using d-electrons theory. The results from these two methods indicate that decreasing C content, increasing B content and doping 0.2-0.3 mass% Hf can balance the desired mechanical properties and phase stability in K44 alloy, which also is confirmed experimentally through the relation between mechanical properties and phase stability of base/modified K44 alloys.

关键词: superalloy K44;neural network;d-electrons theory;mechanical;properties;phase stability;bayesian neural-network;nickel-base superalloys;creep-rupture life;behavior;phase

W44+离子双电子复合速率系数的理论研究

马新泽 , 符彦飙 , 李麦娟 , 张国鼎 , 张义钊 , 董晨钟

原子核物理评论 doi:10.11804/NuclPhysRev.30.02.214

利用全相对论组态相互作用方法，详细研究了W44+离子从基组态3s23p63d104s2俘获一个电子形成双激发态(3s23p63d104s2)?1nln′l′(n=4～6，n′=4～7)的双电子复合(DR)过程。通过比较不同壳层电子激发的DR速率系数，得知4s电子激发和3d电子激发的DR速率系数分别在低温和中高温度时给出了主要贡献，得到了主要的电子激发DR通道。在1 eV～50 keV温度范围内，计算了n=4～18的DR速率系数，并外推到了n=100，得到总DR速率系数。比较总DR速率系数、三体复合(TBR)以及辐射复合(RR)速率系数，结果表明DR速率系数在研究的温度范围内远大于TBR和RR速率系数，其将明显地影响ITER等离子体的电离平衡和离化态布居。

关键词: 双电子复合 , DR速率系数 , W44+离子

Microstructure and mechanical properties of cast Ni-base superalloy K44

Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing

The Ni-base superalloy K44, developed recently in China, plays an important role in manufacturing blades of gas turbine engines due to its high temperature capability. The microstructure, deformation mechanism and mechanical properties of the Ni-base superalloy K44 have been investigated. Tensile properties and creep behaviors show abnormal variations with increasing temperatures, and the creep data can be fitted well with modified Dyson-McLean relation. transmission electron microscopy (TEM) observations confirmed that these behaviors are affected by the gamma' properties and the deformation mechanism at high temperature. On the basis of creep test results, Larson-Miller and Monkman-Grant plots for life prediction are made. The fracture characteristics of Ni-base superalloy K44 alloy at different temperatures and stress are also studied. (C) 2004 Elsevier B.V. All fights reserved.

关键词: k44;microstructures;creep;fracture properties;creep;behavior

形状记忆合金Ti44Ni47Nb9的抗高温氧化性能

陶斌武 , 刘建华 , 李松梅

金属学报 doi:10.3321/j.issn:0412-1961.2005.06.014

采用恒温氧化法,结合x射线衍射(XRD)、扫描电镜(SEM)及能谱分析(EDS)等手段,研究了Ti44Ni47Nb9形状记忆合金(SMA)的抗高温氧化性能.结果表明,Ti44Ni47Nb9合金在450℃下轻微氧化;600-800℃高温下氧化增重曲线符合抛物线规律,氧化膜外层主要是金红石型TiO2,中间为富Nb层,内层为富Ni的Ni3Ti层.研究表明,Ti44Ni47Nb9合金中的Nb元素减少了TiO2中的氧空位,形成的富Nb阻挡层,能有效地抑制Ti元素的外扩散,同时也阻挡了氧的内扩散,降低了氧的固溶度,从而抑制了Ni3Ti层中Ni元素的进一步氧化,提高了合金的抗高温氧化性能.

关键词: Ti-Ni-Nb , 形状记忆合金(SMA) , 高温氧化 , 氧化膜

Ni56Cr44Ti锻造合金的组织和性能研究

陈继志 , 汤文新 , 袁亚民 , 阴辉 , 宁天信

材料开发与应用 doi:10.3969/j.issn.1003-1545.2000.05.003

对Ni56Cr44Ti锻造合金在不同状态下的组织和性能进行了试验和分析.认为此合金具有优良的高温力学性能和耐高温高硫含钒腐蚀性能,特别适用于制造高温高硫含钒环境中的承力构件.

关键词: Ni56Cr44Ti , 组织 , 性能 , 锻造

Ti-(44—50)Al合金定向包晶凝固过程中的组织演化

刘畅 , 苏彦庆 , 李新中 , 郭景杰 , 贾均 , 傅恒志

金属学报

利用TiAl二元系的热力学模型，计算了Ti-(44—50)Al(原子分数，%)合金包晶反应附近的相图，确定了初生相β和包晶相α的固、液相线，得到了界面响应函数所需的部分参数. 利用这些参数及单相合金凝固界面响应函数模型，计算了初生相β和包晶相α的界面温度与生长条件变化的关系；结合最高界面生长温度判据，分析了Ti-(44—50)Al合金凝固过程中的相选择和组织演化，并确定了Ti-Al合金稳态凝固时以成分和G/v为框架的相选择图.

关键词: Ti-Al合金 , peritectic solidification , interface response function (IRF)

微波固化环氧树脂(E44/DDM)的热性能及膨胀性能

刘学清 , 王源升

高分子材料科学与工程

利用微波辐照固化环氧E44/二苯甲烷二胺(DDM)体系,考察了固化温度、固化时间以及微波功率之间的关系,分析了固化过程.利用FT-IR、DSC、热膨胀仪分别表征了体系的固化度、玻璃化转变温度(Tg)、热分解温度以及热膨胀系数(α).结果表明,与热固化过程相比,微波能显著提高E44/DDM的固化速度,缩短凝胶化时间.且微波固化物具有较高的热分解温度和较低的线膨胀系数α.

关键词: 微波固化 , 环氧树脂 , 热性能 , 热膨胀系数

Ni47Ti44Nb9形状记忆合金冲击过程形变行为分析

刘洪涛 , 周吉学 , 刘清 , 刘运腾 , 庄海华

有色金属工程 doi:10.3969/j.issn.2095-1744.2016.06.003

利用轻气炮装置在不同加载速率下对Ni47Ti44Nb9形状记忆合金进行了动态冲击加载试验.采用差示扫描量热仪(DSC)、X射线衍射仪(XRD)和透射电子显微镜(TEM)等先进手段对样品的形变行为进行了分析表征.探讨冲击过程合金样品的物相转变机制和微观组织演化规律.结果表明:冲击后样品内部存在大量微观缺陷,NiTi基体相与β-Nb粒子相均发生了明显的形变,但未发生应力引发马氏体相变过程,这可能是由于Ni47Ti44Nb9合金马氏体相变温度较低以及β-Nb粒子对相变过程的阻碍作用引起的.

关键词: 形状记忆合金 , Ni47Ti44Nb9 , 冲击加载