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1.
制备了纳米级Y-TZP(Y_2O_3稳定的四方ZrO_2多晶)强化Al_2O_3陶瓷复合材料,并研究了其组织性能。发现纳米粉末有利于提高制品的密度和获得细晶组织。有两种ZrO_2粒子存在于该复合材料中,即Al_2O_3晶内的十分细小的ZrO_2粒子和镶嵌于Al_2O_3晶界的ZrO_2粒子,这两种粒子共同作用,十分显著地提高制品的强度,后者还有利于高温性能的改善。20(vol)%(Y-TZP)-Al_2O_3纳米复合材料的抗弯强度和断裂韧性分别达到1750MPa和6.1MPa.m ̄(1/2)。断裂韧性的缓慢提高主要是由于制品的高密度及晶粒细化的结果。  相似文献   

2.
ZrO_2-MoSi_2复合材料及性能研究   总被引:1,自引:0,他引:1  
采用热压法制备ZrO2-MoSi2复合材料。结果表明:复合材料的密度、抗弯强度、断裂韧性受第二相粒子ZrO2含量的影响;在合理的工艺条件下,复合材料的抗弯强度和断裂韧性较基体MoSi2约可提高1~2倍,分别达到550MPa,9.1MPa·m1/2。研究认为,材料性能提高的主要原因在于ZrO2相变增韧及复合材料中存在的残余应力。  相似文献   

3.
通过对TiO2-Al-C体系反应过程的研究,采用反应热压法制备了原位TiC,Al2O3粒子复合增强的TiC-Al2O3/Al复合材料。研究了体系中Al含量对反应合成过程及复合材料致密度的影响,分析了热爆合成TiC粒子的形成机制。研究表明;生成的TiC粒子呈球形,尺寸均匀;且随体系Al含量的提高,TiC合成反应温度降低,TiC颗粒尺寸减小,复合材料的致密度增加,在35MPa的热压下,复合材料可达到  相似文献   

4.
陶瓷钎焊的研究   总被引:2,自引:0,他引:2  
研究了Al_2O_3、93%Al_2O_3、Si_3N_4和ZrO_2陶瓷与陶瓷、陶瓷与不锈钢活性钎焊。结果表明:用Ag-Cu-Ti活性钎料直接钎焊陶瓷与陶瓷可获得良好的接头强度;Cu缓冲层明显影响陶瓷与不锈钢钎焊接头强度。当不加缓冲层或缓冲层太薄(≤0.05mm),焊后不能完整存在而不能有效缓和接头残余应力时,接头有效强度较低;当缓冲层较厚(0.1和0.3mm)时,可获得高的接头强度。  相似文献   

5.
氧化物薄膜对Fe_3Al高温氧化的影响   总被引:1,自引:0,他引:1  
应用电沉积-反应烧结方法在Fe_3Al表面制得Cr_2O_3和Y_2O_3薄膜。在900℃空气中氧化结果表明,表面沉积Cr_2O_3薄膜可以明显提高Fe_3Al的抗氧化能力和氧化层的粘附性;表面沉积Y_2O_3薄膜可以改变氧化层的形貌,抑制氧化层的剥落。XRD,SEM及EDX分析表明,表面施加氧化物薄膜后,氧化产物层晶粒细小,从而减小了生长应力,减轻了开裂和剥落。表面沉积Cr_2O_3薄膜,可以有效地降低Fe_3Al表面的氧分压,促进合金中铝选择氧化。  相似文献   

6.
涂层Ti纤维增强TiAl基复合材料   总被引:2,自引:0,他引:2  
研究了涂覆Al_2O_3的Ti纤维增强γ-TiAl基复合材料,分析了界面结构和力学性能特征。结果表明,采用物理气相沉积法在Ti纤维表面涂覆Al_2O_3增强TiAl基复合材料,使TiAl合金的弯曲强度从449MPa提高到573MPa,即提高了28%;弯曲挠度变化不明显;Ti纤维与TiAl基体间的界面反应层厚度由原来的30μm减小到20μm。  相似文献   

7.
M(NTO)n和M(NTO)n.mH2O的热化学和热力学性质   总被引:6,自引:4,他引:2       下载免费PDF全文
本文着重介绍了用Caivet微量热量计在298.15K下测定了20种M(NTO).·mH_2O(M=金属;NTO=3-硝基-1.2.4-三唑-5-酮;M=Li,n=1,m=2:M=Na,K,n=1,m=1;M=Mg.Mn,Co,Ni,n=2,m=8;M=Ca,n=2,m=4;M=Ba,n=2,m=3;M=Y、Yb,n=3,m=6;M=La,Ce,Pr.Sm,Eu,Gd,n=3,m=7;M=Nd,n=3,m=8;M=Tb;Dy,n=3;m=5)在水中的溶解焓和KNTO·H_2O(cr)与CuSO_4(aq)、Pb(NO_3)_2(aq)和Zn(NO_3)_2(aq)的沉淀反应焓.利用测得的溶解焓和沉淀反应治数据,计算了这20种M(NTO)_n·mH_2O和3种沉淀反应产物(Cu(NTO)_2·2H_2O,Pb(NTO)_2·H_2O和Zn(NTO)_2·H_2O)的标准生成焓。用Kapustinskii公式计算了20种M(NTO)_n(M=Li.Na,K,n=1;M=Mg,Ga,Mn,Co,Cu,Zn,n=2;M=Y,La,Ce,Pr,Nd,Sm,Eu,Gd,Tb,Dy,Yb.n=3)的晶格能,进而算出了它们  相似文献   

8.
采用超微Al2O3粉和热压烧结工艺制备出两种Al2O3基陶瓷(Al2O3-MgO-TiC、Al2O3-MgO-TiC-Y-PSZ)。研究了这两种材料烧结体的密度、显微组织和力学性能。并将烧成陶瓷加工成切削刀片,对35CrMnSiA超高强度调质钢进行切削试验,所得结果与其它几种陶瓷刀具的切削性能进行了比较。  相似文献   

9.
用量子化学中的非限制Hartree-Fock自洽场AM1(UHF+SCF+AM1)方法计算了下达三个反应NH_2NO_2→·NH_2+·NO_2(1)CH_3NHNO_2→CH_3NH+·NO_2(2)(CH_3)_2NNO_2→(CH_3)_2N·+·NO_2(3)的过渡态和活化能,给出了位能曲线。发现它们的活化能与反应物的N-N键级之间存在平行递变关系。PM3计算重现了类似结果。  相似文献   

10.
Al_2O_3/Al复合材料反应生成技术   总被引:5,自引:2,他引:3  
研究运用XDTM法制备金属基复合材料工艺,成功地制备了Al2O3(P)/Al复合材料。试验证明,粒径10~15μm的SiO2粉末与Al粉制成的坯体,在600℃保温3h时反应能全面进行,但直至保温4h时反应仍不彻底;当保温时间延长至6h后,生成的Al2O3粒子中Si含量极小,反应彻底完成。反应生成的Si富集在Al2O3粒子周围的基体中,以细小、球形的结晶体形式析出。生成的Al2O3粒子与基体的界面结合良好。同时对反应机理和反应对基体的影响也作了初步的探讨  相似文献   

11.
Tetraacetyldibenzylhitane (TADBIW) was subjected to debenzylation by nitrosating with inorganic materials available commercially to synthesize tetraacetyldinitrosohexaazaisowurtzitane (TADNSIW). TADNSIW was purified, and its structure was determined by FTIR, 1H NMR, MS and element analysis. The debenzylation reaction of TADBIW gave quantitative benzaldehyde as a by-product. This indicates that the reaction produces an imine cation as an intermediate. Hexanitrohexaazaisowurtzitane (HNIW) was prepared from unpurified TADNSIW with the yield over 96.0 % and the purity more than 98.0 %. And the mechanism of the reaction from TADNSIW to HNIW is proposed to be oxidation of nitroso and nitration of acetyl on the molecule of TADNSIW, This reaction system involved is simple, and the reaction can complete within a short time and under mild conditions. The product can be easily to separate and the waste disposed readily.  相似文献   

12.
The technique of watermarking has been introduced into 2D vector maps for many potential applications such as protecting the copyright of important GIS (geographical information system) data and tracing the data source of military maps. In most previous works, although the validity of the map data could be preserved during the embedding procedure, the shape-distortions of the map elements are usually neglected which would tend to degrade the invisibility of the watermarking schemes. A shape-preserving algorithm for watermarking 2D vector maps is presented in this paper. A 1D distance sequence extracted from the original map is adopted as the cover data instead of 2D coordinates. A watermark bit is represented by changing the distributions of the cover data. The embedding procedure induces lower shape-distortions than in former works. Experimental results indicate better invisibility of the proposed scheme, as well as its robustness to certain attacks such as map simplification, interpolation, additive noise and most geometric transforms.  相似文献   

13.
Open rule-setting method advanced in this paper concentrates on providing designers of engines with a convenient way to express their design innovations and develop the expected prototypes in the early CAD stage, and constitute effective models for the following analysis process of CAE and CAPP. The problems arisen in the process of conceptual design with the traditional experience-based development method are analyzed. Based on those analyses, open rule-setting method is presented and some associated technical problems are discussed. The functional framework of open rule-setting system was built as software engineering methods. The speciality of the engine product as a kind of complex product and the requirement of the engine product based on its structural particularity to rule-setting system are considered carefully. A demonstration is supplied to illustrate how the open rule-setting method enhances the efficiency and quality of the engine conceptual design.  相似文献   

14.
By analyzing the working principle of Linux network device driver, discussing the Linux network driver structure and its key technologies, the general network driver structure and its design methodologies in Linux system are summarized. Through modifying the network device driver of Linux device driver 3rd version snull, c and improving the COW technology, the Zero-Copy technology in Linux (kernel version 2.6.11 ) is implemented. In the end, the success test tells us that the thorough analysis of network device driver is the foundation of many applications, and it also provides a certain improvement to a lot of real applications, even to military application development.  相似文献   

15.
For measuring velocity and impacting position of single fragment of warhead, a non-contact measuring method is proposed, in which a six-light-screen array, a position indicator, a multi-channel chronograph and a computer are used.The principle of measurement is described. The key device of the system is a light screen array sensor which consists of six light screens allocated with certain geometrical parameters. When the fragment flies through the light screen array, the time of passing through each of the screens is recorded by the multi-channel chronograph. According to the time data and the geometrical parameters of the array, the velocity vector and the location of the fragment can be calculated immediately. The presented method can be used to locate the fragment and to measure the real velocity on its flying direction. It can also be used to measure the velocity of a fragment swarm after the system is engineered further.  相似文献   

16.
阐述了数码电子雷管中,点火药剂细结晶三硝基间苯二酚铅(LTNR)的制备工艺;从点火药剂的种类、加入黏合剂的质量分数、桥丝直径、点火头的电阻值、防潮漆的蘸涂等方面对点火头性能的影响因素进行了探讨;通过震动试验、并联起爆试验、延期精度检测与考核,试验结果表明:一次性合成的细结晶LTNR是制造数码电子雷管点火头较为理想的点火药剂,按技术要求生产的点火头性能指标能够满足行业标准要求。  相似文献   

17.
By analyzing the influencing factors of part quality making of sheet alloy of titanium by vibra cutter, the shape of upper reamer is set as cylinder and wedge-shaped form, and the lower reamer as plain and hemicycle form, and its main structural parameters are defined as well. Then it is validated further that such improved vibra cutter reamer can be used to process curve-edged parts of titanium alloy sheet. The experimental result shows that the titanium alloy sheet parts processed by above equipment have no sharpen angles for convex parts and evident crevasse of concave-edged part. In summary, such improvement can eliminate the free-waved edge and improve the manufacture quality of titanium alloy sheet parts greatly.  相似文献   

18.
The initiating behavior of fine-grained explosives by small flyer is studied. The diameter of small flyer in this device is 1 ram. The test results indicate that the granularity of explosives has great effect on its flyer initiating sensitivity.The flyer initiating sensitivity of the fine-grained explosives is higher and the critical initiating energy is lower than that of common explosives. For common explosive, the flyer initiating sensitivity increases as the density is reduced. But for the fine-grained explosive, the test results are exactly opposite.  相似文献   

19.
Multi-laser-target tracking is an important subject in the field of signal processing of laser warners. A clustering method is applied to the measurement of laser warner, and the space-time fusion for measurements in the same cluster is accomplished. Real-time tracking of multi-laser-target and real-time picking of multi-laser-signal are introduced using data fusion of the measurements. A prototype device of the algorithm is built up. The results of experiments show that the algorithm is very effective.  相似文献   

20.
A method to calculate the surface shape error, which is caused by the installing error between the workpiece and the lapping tool in the process of form lapping, is proposed. The mathematical model which the installing translation error influences on the workpiece surface shape error is established. The changing rule of the error is simulated through the calculating example of the paraboloid workpiece. The results indicate that the surface shape error of the workpiece is increasing with the increase of the installing translation error, it is also increasing gradually along the center point of the curve surface to the edge, and the influence is severer to the curve surface with great curvature than that of the small curvature when the translation error is the same.  相似文献   

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