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低层错能镍基单晶高温合金压缩行为和变形组织的温度相关性 被引量:3
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作者 杨文超 屈鹏飞 +6 位作者 刘晨 曹凯莉 秦嘉润 苏海军 张军 任翠东 刘林 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2023年第1期157-167,共11页
在室温至1000℃的范围内,研究温度对一种低层错能镍基单晶高温合金压缩行为和变形组织的影响。研究结果表明,压缩行为和变形组织均表现出温度相关性。室温下该合金具有较高屈服强度,600℃时屈服强度有所下降;随后,随着温度的升高,屈服... 在室温至1000℃的范围内,研究温度对一种低层错能镍基单晶高温合金压缩行为和变形组织的影响。研究结果表明,压缩行为和变形组织均表现出温度相关性。室温下该合金具有较高屈服强度,600℃时屈服强度有所下降;随后,随着温度的升高,屈服强度持续增加,并在800℃时达到最大值;在800℃以上时,屈服强度迅速降低。通过透射电子显微镜观察揭示合金变形机制。位错缠结和位错对塞积是室温下屈服强度较高的主要原因。在600℃时,变形机制从反相畴界切割向堆垛层错切割转变,这导致屈服强度略有下降。在800℃时,变形机制以堆垛层错切割为主,而Lomer-Cottrell锁和不同方向堆垛层错之间的反应导致最大的屈服强度。在900℃及以上时,虽然仍存在一些层错,但主要变形机制为位错绕过机制。最后,讨论变形机制和压缩行为的温度依赖性。 展开更多
关键词 镍基单晶高温合金 位错结构 堆垛层错 压缩行为
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Effects of grain refinement on cast structure and tensile properties of superalloy K4169 at high pouring temperature 被引量:3
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作者 Zi-qi Jie Jun Zhang +4 位作者 Tai-wen Huang Lin Liu hai-jun su Yan-li Shi Heng-zhi Fu 《China Foundry》 SCIE 2016年第2期101-106,共6页
In order to improve the filling ability of large complex thin wall castings, the pouring temperature should be increased, but this will result in the grain coarsening. To overcome this problem, two kinds of grain refi... In order to improve the filling ability of large complex thin wall castings, the pouring temperature should be increased, but this will result in the grain coarsening. To overcome this problem, two kinds of grain refiners of Co-Fe-Nb and Cr-Fe-Nb ternary alloys, which contain high stability compound particles, were prepared. The effects of the refiners on the as-cast structures and tensile properties of the K4169 superalloy with different casting conditions were studied by analyzing specimens 110 mm long and 20 mm in diameter.Results showed that the mixture addition of the two refiners in the melt of K4169 can reduce the columnar grain region and decrease the equiaxed grain size greatly. After refinement, the amount of Laves phase decreases and its morphology changes from island to blocky structure. The carbides in the fine grain samples are fine and dispersive. Meanwhile, the porosity in specimens is decreased due to grain refinement. As a result, the yield strength, ultimate strength and the elongation of the specimens are increased. The grain refinement mechanisms are also discussed. 展开更多
关键词 SUPERALLOY K4169 grain refinement tensile properties
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A practical community-based response strategy to interrupt Ebola transmission in sierra Leone, 2014–2015
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作者 Zhong-Jie Li Wen-Xiao Tu +53 位作者 Xiao-Chun Wang Guo-Qing Shi Zun-Dong Yin hai-jun su Tao Shen Da-Peng Zhang Jian-Dong Li Shan Lv Chun-Li Cao Rui-Qian Xie Hong-Zhou Lu Rong-Meng Jiang Zheng Cao Zhi-Jie An Lei-Lei Li Jie Xu Yan-Wen Xiong Wei Zang Wei Zhang Hong-Wei Zhang Wen-Sen Chen Hua Ling Wen Xu Jian Cai Huan-Jin Luo Xue-Sheng Xing Can-Jun Zheng Qiang Wei Xin-Xu Li Mei Li Hai Jiang Li-Quan Deng Ming-Quan Chen Xiang Huo Feng Xu Xue-Hui Lai Xi-Chen Bai Long-Jie Ye Jian-Yi Yao Wen-Wu Yin Jiao-Jin sun Lin Xiao Fu-Qiang Liu Xiao-Qiang Liu Hong-Wei Fan Zeng-Qiang Kou Ji-Kun Zhou Hao Zhang Da-Xin Ni Thomas TSamba Qun Li Hong-Jie Yu Yu Wang Xiao-Feng Liang 《Infectious Diseases of Poverty》 SCIE 2016年第1期670-679,共10页
Background:The Ebola virus disease spread rapidly in West Africa in 2014,leading to the loss of thousands of lives.Community engagement was one of the key strategies to interrupt Ebola transmission,and practical commu... Background:The Ebola virus disease spread rapidly in West Africa in 2014,leading to the loss of thousands of lives.Community engagement was one of the key strategies to interrupt Ebola transmission,and practical community level measures needed to be explored in the field and tailored to the specific context of communities.Methods:First,community-level education on Ebola virus disease(EVD)prevention was launched for the community’s social mobilizers in six districts in Sierra Leone beginning in November 2014.Then,from January to May of 2015,in three pilot communities,local trained community members were organized to engage in implementation of EVD prevention and transmission interruption measures,by involving them in alert case report,contact tracing,and social mobilization.The epidemiological indicators of transmission interruption in three study communities were evaluated.Results:A total of 6016 community social mobilizers from 185 wards were trained by holding 279 workshops in the six districts,and EVD message reached an estimated 631680 residents.In three pilot communities,72 EVD alert cases were reported,with 70.8%of them detected by trained local community members,and 14 EVD cases were finally identified.Contact tracing detected 64.3%of EVD cases.The median duration of community infectivity for the cases was 1 day.The secondary attack rate was 4.2%,and no third generation of infection was triggered.No health worker was infected,and no unsafe burial and noncompliance to EVD control measures were recorded.The community-based measures were modeled to reduce 77 EVD cases,and the EVD-free goal was achieved four months earlier in study communities than whole country of Sierra Leone.Conclusions: The community-based strategy of social mobilization and community engagement was effective in casedetection and reducing the extent of Ebola transmission in a country with weak health system. The successfullypractical experience to reduce the risk of Ebola transmission in the community with poor resources would potentiallybe helpful for the global community to fight against the EVD and the other diseases in the future. 展开更多
关键词 Ebola virus disease Community engagement Health education Outbreak control
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