共查询到20条相似文献,搜索用时 78 毫秒
1.
2.
3.
含硼黄铜冷凝管使用前后表面膜及耐蚀性的研究 总被引:1,自引:0,他引:1
一种加痕量硼的新型黄铜冷凝管在电厂运行4—5年中显示出较好的耐蚀性。本文用 X 射线、电子探针、离子探针及电化学等方法研究了该冷凝管在使用前后表面膜及腐蚀产物的组织和成分。结果表明:由于硼在退火过程中形成的表面膜中富集,从而提高了冷凝管的防护能力。 相似文献
4.
采用光学显微镜(OM)、扫描电镜(SEM)、X射线衍射仪(XRD)和室温拉伸试验研究了稀土Nd对热挤压Mg-5 0Y-xNd-0.6Zr(x=0,1.0,2.6,4.2,质量分数/ %,下同)合金微观组织和力学性能的影响.结果表明:随着Nd加入量增大,挤压合金中带状分布的β和Mg24Y5相颗粒增多,促进了动态再结晶的形... 相似文献
5.
镁合金消失模铸件表面膜成分及其结构 总被引:2,自引:0,他引:2
采用X射线光电子能谱技术(XPS)对消失模镁合金铸件的表面成分进行了测定,结果表明消失模镁合金铸件表面元素成分为Mg、Al、C、O、Si;结合对镁合金液和消失模样界面间的化学反应分析,揭示了消失模镁合金铸件表面是由MgO、Al2O3、SiO2和无定型C等组成的一层薄膜,即消失模镁合金铸件表面的Al2O3-SiO2-MgO-C复合膜;该复合膜对提高镁合金表面的防腐蚀性有很好的作用;提出了镁合金消失模表面膜的结构模型.这些结果表明,消失模技术作为镁合金零件的成形方法具有独特的优势. 相似文献
6.
7.
8.
9.
10.
研究了添加Cu对热挤压Mg-3Sn-1Zn合金显微组织和力学性能的影响。结果表明:添加少量Cu能显著细化热挤压Mg-3Sn-1Zn合金晶粒,同时在合金中形成具有高热稳定性的CuMgZn相,提高了合金的室温及高温强度和塑性。当Cu含量为0.5%时,热挤压Mg-3Sn-1Zn-0.5Cu合金的晶粒最细,为2.8 μm;其强度和塑性最高,室温屈服强度为241 MPa,伸长率为20.3%,150 ℃时屈服强度为128 MPa,室温拉伸力学性能优于挤压态AZ31B合金,高温强度优于铸态AE42合金。 相似文献
11.
12.
将Al2O3-TiC陶瓷材料与具有固体润滑特性的Al2O3-TiC-CaF2陶瓷材料进行叠层,通过真空热压烧结制备Al2O3-TiC/Al2O3-TiC-CaF2复合叠层陶瓷材料.在环盘式摩擦磨损试验机上进行摩擦磨损实验,研究该材料在不同载荷、转速条件下的摩擦系数和磨损率,分别用SEM及EDS观察材料磨损前后的微观形貌和分析其成分组成,研究其磨损机制.结果表明:在相同载荷条件下,Al2O3-TiC/Al2O3-TiC-CaF2复合叠层陶瓷材料的摩擦系数和磨损率随着转速的升高而下降,在相同转速条件下,其摩擦系数和磨损率随着载荷的增加而下降;Al2O3-TiC/Al2O3-TiC-CaF2复合叠层陶瓷材料的磨损机制主要是磨粒磨损和黏着磨损. 相似文献
13.
14.
采用压铸工艺制备Cu含量为5%~20%(质量分数,下同)的Al-Cu合金试样。在布氏硬度计上测定试样的硬度,利用球盘往复式磨损试验机进行3种载荷(1~5 N)的磨损实验,通过SEM和EDS分析不同Cu含量试样的磨损机理。结果表明:随着Cu含量从5%增加至20%,Al-Cu合金中θ相的体积分数由2.00%增加到25.80%,且θ相的尺寸逐渐增大;硬度从59HB增加到170HB。摩擦因数在0.4~0.85范围内变化;Al-Cu合金试样的比磨损率随Cu含量增加先急剧降低后趋于平缓,Cu含量达到15%以上合金试样比磨损率变化不大,最低比磨损率在4.1×10^(-4)mm 3·N^(-1)·m^(-1)左右;较低Cu含量试样的比磨损率随载荷变化显著,随着Cu含量增加比磨损率差别减小。Al-Cu合金的主要磨损机制为黏着磨损和磨粒磨损,低Cu含量试样以黏着磨损为主,高Cu含量试样以磨粒磨损为主;随着载荷的增加,低Cu含量试样黏着磨损程度增加,高Cu含量试样磨粒磨损程度增加。 相似文献
15.
A. Röttger M. Karlsohn W. Theisen P. Silva S. Weber A. Pyzalla 《Materialwissenschaft und Werkstofftechnik》2008,39(11):830-838
Materials with high resistance against abrasive wear are of interest for many tool applications. For economical reasons, thick coatings of several millimetres are requested. The cladding of these materials to low alloyed substrates is commonly performed using hot isostatic pressing, being a cost intensive process in particular for long products. Thus, a novel manufacturing route via direct hot extrusion of encapsulated bulk steel bars and presintered tool steel powders was recently developed. In this manner, wear resistant claddings of PM tool steels and wear resistant MMC on steel substrates could be processed. Heating to process temperature leads to presintering of the powder and only a weak bonding between the steel substrate and the powdery layer. However, after direct hot extrusion at 1150 °C an interface free of macroscopic defects is formed between both materials. The quality and strength of this bond zone was investigated by micro tensile, 4 point bending and shear tests for different materials combinations. For high strength substrate materials, failure always occurs in the brittle wear resistant layer and not at the interface. These results are in agreement with microstructural investigations, exhibiting a pore‐ and defect‐free interface dominated by interdiffusion processes. 相似文献
16.
The fatigue life of aerospace components depends greatly on the mechanical properties of the finished surface layer. However, no independent strength test of this layer has been reported because of the lack of suitable samples. Therefore, a direct method of assessing the surface tensile strength using film samples with thicknesses of approximately 40 μm is proposed in this paper. The immediate objective of this research is to demonstrate the fundamentals of surface strength testing and prove the feasibility of preparing films by tracking the evolution of the surface integrity. The test results show that layer‐by‐layer grinding and polishing is a feasible method for preparing film samples with sufficient area, controllable thickness, and well‐maintained surface integrity. During the preparation of the film samples, the roughness and micro‐hardness of the test side (the side kept unprepared for testing) are protected, and those of the processed side (the side that is ground and polished) are controlled. The residual stress on both sides is released to zero. The film specimens exhibit regular fracture behaviour in the tensile tests, and their stress–strain curves can be explained as weighted averages of the stress–strain functions of multiple layers. 相似文献
17.
The structure and composition of the surface oxide film on the 5083 aluminium alloy at a brazing temperature of 500°C were investigated by transmission electron microscopy and X-ray photoelectron spectroscopy. The results showed that the original γ-Al2O3 film on the surface of the cold rolled 5083 aluminium alloy was transformed into a complex oxide film consisting of MgO, MgAl2O4, and free Al atoms after heating. The thickness of this oxide film, which could be divided into two distinct layers, was approximately 130 nm. The outer layer was mainly composed of an amorphous MgO phase, while the inner layer was MgO based, with a few free Al atoms and a small number of nanocrystalline MgAl2O4 particles distributed in it. 相似文献
18.
电沉积铁镍纳米合金薄膜的结构和性能研究 总被引:3,自引:0,他引:3
采用电沉积方法从硫酸盐体系镀液中沉积得到Fe18Ni82合金薄膜.运用扫描电子显微镜(SEM),原子力显微镜(AFM),透射电子显微镜(TEM)和X射线衍射分析(XRD)以及磁测量设备分别对薄膜的表面形貌、显微结构和磁性能进行表征和测量.同时利用万能材料试验机和显微硬度计测量了薄膜的力学性能.结果表明:电沉积制备的Fe18Ni82合金薄膜成分均匀,表面平整、光亮、致密,晶粒大小为40~50 nm.薄膜是以Ni为溶剂原子,Fe为溶质原子的置换型固溶体,只存在单一的fcc相,Fei8Ni82合金薄膜沿(111)面有较强的择优取向.镀态Fei8Ni82合金薄膜在50 Hz交流磁场下,测得其饱和磁感应强度为1.08 T,最低矫顽力为20 A/m.19 μm厚的纳米晶薄膜的断裂应力达到785MPa,显微硬度达到605Hv. 相似文献
19.
20.
胞状铝(合金)的准静态压缩性能 总被引:2,自引:0,他引:2
测量了新型轻质(0.14ρ0 ~0.09ρ0,ρ0 为纯铝的密度)高强度胞状铝合金(ZL111)和胞状纯铝的压缩应力(σ) 应变(ε)曲线。胞状铝合金的压缩屈服强度σs比胞状纯铝高40%以上,其σε曲线呈锯齿状,平台斜度(dσdε)比后者小。提出了确定泡沫金属材料致密化起始点εD 的方法,为实际应用和科学研究提供了依据。 相似文献