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1.
定向凝固钴基合金DZ40M高温缺口疲劳性能及其断口研究   总被引:4,自引:3,他引:1  
研究了定向凝固钴基高温合金DZ40M700℃和900℃缺口疲劳性能有疲劳断口。结果表明,DZ40M合金具有较高的抗高温缺口疲劳破坏能力,700℃和900℃缺口疲劳强度分别为285MPa和203MPa,且表现出低的疲劳缺口敏感性,700℃和900℃疲劳缺口敏感度仅为0.146和.153。在交变载茶作用下,700℃缺口疲劳裂纹是以小平面方式,沿着{111}滑移面扩展,而900℃缺口疲劳裂纹是在交变载荷  相似文献   

2.
杨富民  孙晓峰等 《金属学报》2002,38(10):1053-1056
研究了K40S钴基高温合金在700℃和900℃温度条件下由应变控制的高温低周疲劳行为,对疲劳断口形貌进行观察,结果表明;在高温低周疲劳加载条件下,K40S合金疲劳裂纹萌生机制为表面滑移带开裂与表面碳化物相界面开裂的综合作用;疲劳裂纹萌生与扩展方式为穿晶型,瞬断区呈现枝晶断裂特征;碳化物可作为障碍,阻碍疲劳裂纹的扩展,且为主要的二交裂纹策源地;K40S合金高温低周疲劳断裂为机械疲劳与高温环境氧化共同作用的结果。  相似文献   

3.
研究了K40S钴基高温合金在700℃和900℃温度条件下由应变控制的高温低周疲劳行为,对疲劳断口形貌进行观察,结果表明:在高温低周疲劳加载条件下,K40S合金疲劳裂纹萌生机制为表面滑移带开裂与表面碳化物相界面开裂的综合作用;疲劳裂纹萌生与扩展方式为穿晶型,瞬断区呈现枝晶断裂特征;碳化物可作为障碍,阻碍疲劳裂纹的扩展,且为主要的二次裂纹策源地;K40S合金高温低周疲劳断裂为机械疲劳与高温环境氧化共同作用的结果.  相似文献   

4.
姜文辉  姚向东 《金属学报》1999,35(3):253-256
本文研究了新近开发的定向凝固DZ40M钴基高温合金在700℃,360-340MPa时蠕变形变特点,用扫描电镜和透射电镜分别观察了蠕变断裂断口、纵向剖面和形变后组织结构.结果表明:DZ40M合金700℃起始蠕变阶段蠕变应变和间呈线性关系;稳态蠕变速率可用ε=A exp(b/kT)来表示,其中 A=8.7270×10-13%h-1 b=0.9039×10-21cm3·DZ40M合金表现出高的蠕变塑性;在蠕变过程中,大量细小的 M23C6在基体中沉淀析出,它们有效地强化合金基体; 蠕变断裂为穿晶韧性断裂,裂纹萌生于初生碳化物本身以及与基体的界面裂纹在垂直应力轴方向上扩展,最终导致穿晶断裂。  相似文献   

5.
定向凝固合金DZ17G的高温低周疲劳性能研究   总被引:6,自引:0,他引:6  
研究了定向凝固镍基高温合金DA17G在800℃下的低周疲劳性能,得到其循环应力-应弯曲线和应变-寿命曲线,并用最小二乘法回归至Manson-offin方程的数学表达式;对疲劳断口进行了宏观及微观分析,发现裂纹主要在试样内部及近表面缺陷外萌生,裂纹一旦形成即穿晶扩展,且扩展方向垂直于加载轴。  相似文献   

6.
Ti3Al基合金的应变疲劳性能   总被引:1,自引:0,他引:1  
详细研究了TD2合金(Ti3Al基)650℃下低循环应变疲劳性能。依据实验数据利用回归分析计算出应变疲劳参数,得出该合金应变疲劳寿命预测公式,并分析了应力—应变行为。实验结果表明Ti3Al基合金应变疲劳性能优于GH33高温合金,与DZ4高温合金760℃水平相当。在循环过程中表现出循环硬化的特征。同时还讨论了TD2合金疲劳裂纹的起源与扩展。  相似文献   

7.
在定向凝固钴基高温合金中采用V型缺口分别垂直和平行于凝固方向的板状热疲劳试样,并在缺口位置预制再结晶组织,研究了在最高温度为1000℃,最低温度为室温的冷热循环下,缺口取向和再结晶对定向凝固钴基高温合金热疲劳性能的影响.结果表明,缺口取向垂直于凝固方向时,基体在应力作用下循环氧化开裂;缺口平行于凝固方向时,热疲劳性能下降,裂纹沿枝晶间扩展.再结晶降低定向凝固钴基高温合金的热疲劳性能,再结晶晶界氧化开裂,晶界析出的M23C6型碳化物氧化脱落后形成的孔洞加速了裂纹扩展;连接枝晶间碳化物的再结晶晶界成为缺口平行于凝固方向时热疲劳裂纹的优先扩展通道.  相似文献   

8.
M38镍基高温合金高温低周疲劳性能及断裂机制   总被引:4,自引:0,他引:4  
对铸造镍基高温合金M38在900 ℃下的低周疲劳行为进行了研究.采取轴向总应变控制,应变比为-1,应变速率为1×10-2 s-1.实验结果表明:M38在900 ℃下具有与IN738LC接近的疲劳性能.在高应变幅时,疲劳裂纹主要萌生在表面碳化物等应力集中处;在低应变幅时,氧化对裂纹的萌生起重要作用,疲劳裂纹主要萌生于与试样表面相连的易氧化的富Cr晶界处和富Ti的碳化物处.在所有应变幅下,疲劳裂纹均沿垂直应力轴的方向穿晶扩展.  相似文献   

9.
DD6单晶高温合金低周疲劳断裂特征的研究   总被引:3,自引:0,他引:3       下载免费PDF全文
对DD6单晶高温合金在高温低周(980℃、760℃)及疲劳/蠕变交互作用的断裂特征进行了研究。结果表明:DD6单晶高温合金高温低周疲劳断口往往呈多源开裂特征,裂纹萌生于试样的表面或亚表面,疲劳裂纹在刚萌生时沿着一定的小平面进行扩展,扩展区主要由垂直于裂纹扩展方向的疲劳条带和河流花样组成,瞬断区为类解理台阶形貌,裂纹扩展初期断口基本与主应力方向垂直,随着疲劳裂纹的扩展,断口呈现与主应力约成45°的平面特征;低周疲劳/蠕变交互作用的断裂特征与相同应变条件下低周疲劳断口总体形貌相似,但也一些不同之处,如断口整体氧化严重、疲劳扩展区面积明显减小。  相似文献   

10.
利用自制的自约束型热疲劳试验机、光学显微镜及电子扫描显微镜研究了碳化物类型不同的4种合金白口铸铁的热疲劳行为。结果表明:具有M7C3型碳化物的18Cr2W及15Cr3Mo合金铸铁的热疲劳抗力最高,而具有M6C型碳化物的25W4Cr及具有M3C型碳化物的3Cr合金铸铁的热疲劳抗力均较低;碳化物是热疲劳裂纹扩展的主要通道,热疲劳裂纹长大通过主裂纹与其前沿碳化物中形成的微裂纹之间“桥接”方式进行,热疲劳断口主要为解理断口。  相似文献   

11.
Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.  相似文献   

12.
The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.  相似文献   

13.
In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.  相似文献   

14.
After nearly two years' tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry (SRIF), located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.  相似文献   

15.
韩磊 《腐蚀与防护》2015,36(1):84-90,94
综述了常见的电化学噪声数据处理方法,介绍了直流趋势剔除、统计分析、快速傅立叶变换(FFT)法计算功率谱密度(PSD)以及小波变换处理电化学噪声信号的基本过程,并阐释了各种数学处理及所得参数的物理意义。  相似文献   

16.
正I take great pleasure in congratulating CHINA FOUNDRY journal on its 10th anniversary.The CHINA FOUNDRY journal started ten years ago.Since its inaugural,China has seen exceptional growth in the Castings Sector and rapid development in Machinery Industry.The journal is becoming an important communication platform for experts  相似文献   

17.
正Harbin General Hydraulic Machinery Works Co.,Ltd.of Yilin Hydraulic Group is the most professional production base of large-scale metallurgy oil cylinder and oil machinery cylinder in the Northeast of China.The main products include metallurgy cylinder,swell-shrink cylinder,rotating injection device,lifting cylinder,main lifting jack,front lifting jack,engineering oil cyl-  相似文献   

18.
正Weihai HHH Mach.Elec.Group is the most technical company focusing on Power transmission and Hydra-controlling.HHH has the ability of developing and testing of complete sets of transmission system with relevant technical training.HHH provide efficient,excellent cost-effective power transmission system and intelligent electric fluid transmission and control system to OEM customers,who are  相似文献   

19.
《中国铸造》2014,(5):460-463
The 9th China International Diecasting Congress and the 1st International Symposium on Nonferrous Alloys and Special Casting Technologies (ISNASCT) were successfully held in Shanghai on July 19-22, 2014. Both events were jointly sponsored by Chinese Mechanical Engineering Society, Die Casting Commission of World Foundry Organization and Non-Ferrous Materials Commission of World Foundry Organization, and organized by the Foundry Institution of Chinese Mechanical Engineering Society (FICMES) and China Productivity Promotion Center of Foundry Industry.  相似文献   

20.
《中国铸造》2014,(6):539-539
The ANKIROS/ANNOFER/TURKCAST shows held on Sept. 11-14, 2014, in Istanbul, Turkey, provided an ideal opportunity for the World Foundry Organization Executive Board to meet and discuss member benefits. Nine executive board members attended the meeting, including Dr. Lou Yanchun, Vice President of FICMES and President of Shenyang Research Institute of Foundry. During the board meeting, the WFO executives agreed to establish a special working group which is responsible for drafting a strategical plan for the WFO and submitting it for discussion at the next board meeting in 2015.  相似文献   

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