K.M. Chang(Department of Mechanical and Aerospace Engineering
,
West Virginia University
,
P.O. Box 6160
,
Morgantown
,
WV 26506
,
USA Manuscript received 26 August 1996)
金属学报(英文版)
P/M superalloy disks obtain their final strength by appropriate heat treatments; the maximum attainable strength depends on the rapid cooling rate from the solution annealing. A rapid quench of a large disk forging can cause two problems, surface cracking and shape distortion.In the past,many attempts employ the finite element code to model and to predict temperature evolution and induced stress distribution in a large turbine disk. The major difficulty was the correct description of alloy behavior; particularly the thermomechanical properties and the failure criteria of material during the cooling. High temperature fatigue resistance is always the key requirement for disk materials. New methodology of residual life management emphasizes the initiation as well as the propagation of the cracks developed under the service conditions. One of major challenges to P/M superalloys is the time-dependent behavior of fatigue cracking, which relates to the well-known SAGBO (stress-assisted grain boundary oxidation) phenomenon.A great effort has been done to understand the micro-mechanism of time-dependent fatigue crack propagation resulted in the second generation of P/M superalloys. Further improvement on temperature capability of disk alloys at rim area may lead to the idea of dual-property disks.Different grain structures at different portions of a large disk are possible,as the property requirements for different locations are different. This goal is achievable if the thermal history at specific disk locations can be controlled to develop desirable microstructures and properties.Some suggestions on the future direction of research efforts will be discused.
关键词:
:superalloy disk
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null
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null
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null
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null
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null
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刘文西
,
王冰辉
,
种克端
,
张存信
金属学报
用电镜观察、电解提取相分离、X射线衍射和电子探针分析的综合方法研究了6Cr4Mo3Ni2WV钢的碳化物相。在1120℃淬火时,钢中未溶碳化物中存在有碳原子长程有序的M_2C和碳原子空位短程有序的V_4C_3。观察到回火析出时V_4C_3与M_2C的伴生成核。确定了合金元素在钢基体和碳化物之间的分配。
关键词:
肖翔
,
刘国权
,
胡本芙
,
万迪
,
陈少静
材料科学与工艺
利用Gleeble-1500热模拟试验机研究了一种12Cr3WV低活性铁素体/马氏体钢在1 223～1 373 K,应变速率0.01 ～30 s-1条件下应变量为60％的热压缩变形行为.分析了不同温度和应变速率对实验钢热变形行为的影响,并采用应变硬化速率-应力曲线图较精确地确定了流变曲线中各特征应力应变值.研究结果表明:高温变形时铁素体的存在会抑制奥氏体的动态再结晶;实验钢的热变形激活能和应力指数分别为347.05 kJ/mol和4.11;建立了热变形本构方程,并回归出峰值应力及临界应力与Zener-Hollomon的关系式.
关键词:
12Cr低活性F/M钢
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热变形行为
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双曲线本构方程
俞学节
金属学报
用电镜薄膜技术研究了6Cr4Mo3Ni2WV基体钢的淬火和回火态的组织结构,着重观察了硬度-回火温度曲线峰值附近的结构,指出合金的二次硬化主要由V_4C_3和M_2C沉淀产生.回火时沿马氏体内孪晶界和{112}晶面析出的片状渗碳体,低于450℃是稳定的,高于500℃是亚稳相,它在回火过程中转变为V_4C_3,M_2C和新的细化渗碳体,这对二次硬化也有贡献;但更主要的是这种转变使合金的冲击韧性α_K值显著提高.在600—650℃亚稳渗碳体的转变区复合转变为M_6C和Cr_7C_3,同时沿原始奥氏体晶界和亚晶界析出连续的等轴M_6C和Cr_7C_3,这一过程又使α_K值下降.
关键词:
罗雅
,
雷玉成
,
龚晨诚
,
梁申勇
材料工程
doi:10.11868/j.issn.1001-4381.2015.01.011
为改善MGH956合金TIG焊焊缝的组织与性能,采用原位合金化方法对该合金进行TIG焊接.对比不同含量V的填充材料对焊缝组织与性能的影响,并讨论了V的作用机理.OM和SEM结果表明:填充材料中添加不同含量的V后,组织出现了不同程度的细化及均匀化,当wv=1.5％时,晶粒最细、尺寸均匀,同时焊缝中的气孔量有所减少;对焊缝中的颗粒进行物相鉴定可知,除了有YAlO3,TiC和TiN颗粒生成外还有(Ti,V)C复合颗粒生成.由TEM观察显示wv=1.5％时,焊缝内的碳化物颗粒与焊缝基体结合良好,且wv-1.5％时,接头强度最高,并实现了接头断裂方式由完全脆性断裂转变为韧性断裂.
关键词:
MGH956合金
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原位合金化焊接
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V
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组织
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性能
PENG Jun
,
WANG Shijun
,
DONG Yuanchi
,
LIU Lixia
,
ZHOU Yun
,
CHEN Erbao
钢铁研究学报(英文版)
The solubility of nitrogen in the FeCVN system was measured at 1 708 K and the model of calculating activity (action concentration) of nitrogen (N) and vanadium (V) was derived according to the phase diagram and the coexistence theory of the metal melt structure. The solubility expression of nitrogen in the FeCVN system at 1 708 K was wN=0058 194-0010 367wC+0005 543 4wV. Comparing the computing results with the experimental results, a satisfactory conclusion could be obtained. The analysis of the FeCVN system using this model showed that VN was present in a high temperature metal melt, which would reduce the action concentration of nitrogen obviously. It was consequently disadvantageous to the removal of nitrogen from hot metal.
关键词:
metal melt;coexistence theory;action concentration;activity
王辉
,
薛向欣
,
杨合
,
李述贤
钢铁钒钛
采用高温固相法制备了V5+掺杂含钛高炉渣光催化抗菌材料.以大肠埃希氏菌、金黄色葡萄球菌、白色念珠菌、腊样杆菌为实验菌种,以普通日光灯为光源,考察了菌种、掺杂量等因素对材料抗菌性能的影响.并采用XRD、SEM等方法对材料进行表征.结果表明:V5+掺杂含钛高炉渣光催化抗菌材料对白色念珠菌抗菌性能较好,并随掺杂量增大抗菌性能增强;用琼脂稀释法测得MIC为wv2o5=2.5%;抗菌材料经生理盐水和无水乙醇洗涤后重复利用其抗菌性能略有下降.
关键词:
光催化
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V5+掺杂
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含钛高炉渣
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高温固相法
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抗菌性能
杨雄飞
,
于浩
钢铁研究学报
为降低传统的Nb-V复合微合金化Q460建筑用钢板中的合金含量及生产成本,利用第3代TMCP技术和V-N微合金化技术,研制出单独V-N微合金化(wv =0.06％～0.08％)、不含铌的合金设计,并通过合理地控轧控冷工艺,在中厚板轧机上成功地生产出厚度40和50 mm的V-N微合金化Q460GJC钢板.产品具有良好的综合性能,屈服强度大于470 MPa,0℃冲击功超过150J,屈强比仅为80％.分析表明,细晶及析出强化对强度的贡献比例达到66％.
关键词:
V-N微合金化
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TMCP
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Q460
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中厚板
李达岗
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江来珠
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金学军
,
王治宇
,
许海刚
钢铁研究学报
利用Thermo-Calc热力学软件、扫描电子显微镜、X射线衍射仪及透射电镜等分析方法,研究了不同钒含量对单铌稳定18Cr-2Mo铁素体不锈钢微观组织、力学性能和点腐蚀性能的影响规律.结果表明:添加钒后的析出相主要是NbC和VN,弥散分布于晶内和晶界,其中NbC的尺寸为100～250 nm;随着钒含量的增加,试验钢的晶粒尺寸及屈服强度变化不明显,而冲击韧性及点腐蚀性能逐步得到改善和提高,当wv=0.36％时,钢的韧脆转变温度由原始的-10℃下降至-30℃,点腐蚀电位由0.38V提高至0.42V.
关键词:
铁素体不锈钢
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钒微合金化
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微观组织
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冲击韧性
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点腐蚀性能
