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1.
钛合金/镍/不锈钢网的扩散连接技术   总被引:3,自引:0,他引:3  
研究了以Ni为中间过渡层时,钛合金与不锈钢网的扩散连接技术,分析了影响扩散连接的主要因素和接头微观组织,确定了最佳工艺参数,并获得了剪切强度达146MPa的无变形接头。  相似文献   

2.
采用高能喷丸(HESP)对TA17钛合金与0Cr18Ni9Ti不锈钢棒材端面表面进行自纳米化(SSNC)处理;采用镍箔作为中间层,在不同温度(800~875℃)下对处理后的钛合金/不锈钢进行脉冲加压扩散连接(PPDB).对接头剖面组织进行金相观察;在拉伸试验机上测试接头拉伸强度,对断面进行SEM,EDS和XRD结构物相分析.研究结果表明:在850℃时接头拉伸强度达到最高,为322.8 MPa;连接后接头界面处纳米晶粒没有完全长大,存在细晶粒区;镍箔有效地阻止了Fe-Ti脆性金属间化合物的形成,在接头处形成β-Ti,(Fe,Ni)固溶体和Ti-Ni金属间化合物(Ti2Ni,TiNi,TiNi3);断裂发生在Ni层与Ti-Ni金属间化合物界面处.  相似文献   

3.
采用化学镀工艺,在Q235基材上制备出2-4μm的Cu-Mn合金化学镀层.在650℃-870℃温度范围内对化学镀层进行了真空扩散焊接试验.利用金相和扫描电镜对接头进行了微观组织和能谱分析。并用拉伸试验评价了接头的连接强度.研究结果表明,在相同工艺参数条件下,镀有Cu-Mn化学镀层的试件其剪切强度比无镀层试件提高1倍以上;高温扩散焊接时接头的连接强度提高,但基体组织比低温扩散焊接时显著粗化.图3。表2。参7.  相似文献   

4.
选取纯Ni箔作过渡层,采用真空热压扩散工艺,在加热温度480℃、压力10MPa、真空度1.0×10^-21Pa的工艺条件下,制备了变形铝合金2024和不锈钢0Crl8 Ni9Ti双金属复合材料.利用扫描电子显微镜、能谱仪、X射线衍射仪和显微硬度仪等测试分析方法,对双金属复合材料的2个连接界面及基体进行了组织、性能分析.结果表明:不锈钢/纯Ni界面形成了宽约8μm的互扩散区,但其过渡区无金属间化合物生成;Al/Ni界面生成了宽约4μm的扩散过渡区,过渡区的相组成为金属间化合物Al3Ni2、Al3Ni及Al3Ni5.  相似文献   

5.
对铁合金TC4与不锈钢ICrl8Ni9Ti异种金属扩散焊接头的结合性能进行了试验研究,利用光学显微镜、扫描电镜、电子探针仪等对接头进行了微观分析.结果表明:TC4/1Cr19Ni9Ti直接扩散焊时,由于母村组元的相互扩散和迁移,在交界面附近形成了金属间化合物层,而导致接头脆断.采用钒十铜作中间过渡金属,则有效地防止了Ti与Fe、Cr、Ni的相互扩散和迁移,保证了钛合金TC4与不锈钢1Cr18Ni9Ti的良好连接.接头的强度与软质中间层铜的厚度有关,最高强度可接近母材不锈钢的下限.  相似文献   

6.
Al-不锈钢连接中的Ni层阻碍机理   总被引:10,自引:0,他引:10  
用试验的方法研究了Al-不锈钢Ni/Cu电刷镀过渡层钎焊中Ni层的作用,并对Ni层进行了机理分析。对焊缝的界面作拉力试验、X射线衍射、 能谱分析(EDAX)和透射电镜(TEM)等分析发现,镀层与钎料等各 面连接紧密,特别是钎缝与母材之间没有生成脆性的金属化合物。说明面心立方结构的Ni层能有效地阻挡Al、Fe等原子扩散,钎缝与镀Cu界面上虽然生成了少量的AlCu3,但不影响焊缝的强度,接头的强度能达到33.6MPa。  相似文献   

7.
钛合金与不锈钢的可靠连接是钛合金与不锈钢实现连接的一个基础性问题,采用热喷涂在不锈钢表面预制Ni涂层,研究Ni涂层作为过渡层,Ag45CuZn为钎料时,钛合金与不锈钢搭接电阻钎焊的实现过程,探讨Ni涂层对接头组织和力学性能的影响.接头力学性能测试表明:Ni涂层的介入使接头剪切强度显著提高,最高可达约243MPa.接头断口形貌及组织的SEM、EDS和XRD等分析表明,Ni涂层中Ni元素不但参与了钎料的冶金反应,而且作为物理层改变了母材中Fe、Ti等原子向对侧扩散,从而获得多种Ni基化合物混合的接头组织,这是钛/钢异质钎焊接头力学性能得到明显提高的主要原因.  相似文献   

8.
为改善铝和不锈钢的焊接接头性能,在奥氏体不锈铜(1Crl8Ni9Ti)的表层热浸镀一层ZL102铝合金,然后采用搭接的形式,应用火焰钎焊工艺进行纯铝(1060)板与奥氏体不锈钢板的焊接。利用金相显微镜和扫描电镜分析焊接接头的微观组织,并用显微维氏硬度仪和万能实验机床测定其显微硬度和拉伸性能。结果表明,通过不锈钢表面热浸镀铝,可实现铝与奥氏体不锈钢的火焰钎焊。在不锈钢/纯铝钎焊焊缝中存在不锈钢/热浸镀铝层、热浸镀铝层/钎缝、钎缝/纯铝三个界面。钎焊接头强度取决于各界面的连接质量。热浸镀铝层/钎缝界面是整个接头中最薄弱的界面,剪切断裂均发生在该区域。钎焊接头各区域中,热浸镀铝区硬度最高,达到99.4MPa。  相似文献   

9.
许多工程结构当中,经常出现大量异种材料的焊接情形,材料的力学性能对结构有重要影响。应用不同的焊接工艺对紫铜(T2)和奥氏体不锈钢(1Cr18Ni9Ti)进行焊接,并对焊接接头的力学性能进行研究。结果表明,采用过渡层方法接头的力学性能较好,而采用T107焊条,其接头的塑性、韧性比采用过渡层时低。  相似文献   

10.
选取纯Ni箔作过渡层,采用真空热压扩散工艺,在加热温度480℃、压力10 MPa、真空度1.0×10-2Pa的工艺条件下,制备了变形铝合金2024和不锈钢0Cr18Ni9Ti双金属复合材料.利用扫描电子显微镜、能谱仪、X射线衍射仪和显微硬度仪等测试分析方法,对双金属复合材料的2个连接界面及基体进行了组织、性能分析.结果表明:不锈钢/纯Ni界面形成了宽约8μm的互扩散区,但其过渡区无金属间化合物生成;Al/Ni界面生成了宽约4μm的扩散过渡区,过渡区的相组成为金属间化合物Al3Ni2、Al3Ni及Al3Ni5.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

14.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

15.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

16.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

17.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

18.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

19.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

20.
1 Rise of studies on climate change's effects on biodiversity
Until the 1980s, climate change and biodiversity were studied as two independent disciplines for more than a century. In 1992, the Ecological Society of America's annual report named climate change, biodiversity, and the sustainable ecological system as the three major global environmental issues of the twenty-first century [1].  相似文献   

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