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排序方式: 共有143条查询结果,搜索用时 31 毫秒
1.
研究了Ce对Al—16%Si合金熔体粘滞性的影响。结果表明:Ce的加入增加了合金熔体的粘度,且随着Ce含量的增加粘度值也增加。结合加入Ce的Al—16%Si合金氢含量的变化、凝固组织和DSC曲线研究了熔体结构的变化,分析了粘度与液态结构变化之间的关系。 相似文献
2.
Sand casting process and directional solidification technique combining thermal-rate treatment(TRT) were used. The influence of process parameters on TRT was investigated according to the values of impact toughness. At the same time, the mechanism of TRT was discussed. The results showed that TRT can improve the impact toughness of this alloy, while the hardness is basically constant. The time of heat preservation should not be more than 5min. Different forms of cooling intensification additive have different effects among which the zinc ingot solidified in graphite mold is the best one that can improve impact toughness of samples by more than 80%. With increasing the cooling temperature, the value of α(Al) crystal lattice constant increases. The element Sb has negative effect on TRT. 相似文献
3.
综述了机械合金化A1-Cu-Fe准晶相的形成机理及热力学稳定性方面的研究进展. 相似文献
4.
针对A1-Cu系高强度铸造合金研制了一种新型盐类晶粒细化剂,使合金晶粒明显细化,机械性能有显著的提高。试验结果表明,该细化剂具有长效性和很强的抗衰退能力,替代中间合金进行细化处理具有操作方便、加入量少和细化效果好等优点,有很高的经济价值。 相似文献
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In-situ TiB2 particles reinforced ZA27 composite was prepared by the stir-casting technique and a twostep method. TiB2/Al composite was produced by incorporating K2 TiF6, KBF4 salts and other agents into Al melt. As a master alloy, TiB2/Al composite was used to manufacture TiB2/ZA27 composite, which results in the generation of well-distributed reinforcing TiB2 phase. The hardness, friction and wear behavior of TiB2/ZA27 composite were investigated. The results show that the hardness of the composite is enhanced with increasing the content of TiB2 particles, the incorporation of TiB2 reduces the wear rate of TiB2/ZA27 composite and improves the friction property under lubricated and dry sliding friction conditions. The worn track width of ZA27 alloy is 1.6 and 2.5 times as long as that of 2.1%TiB2/ZA27 composite at 150 N and 700 N load under lubricated conditions, which indicates that TiB2/ZA27 composite possesses higher bearing ability. 相似文献
7.
耿红霞 《稀有金属材料与工程》2016,45(3):612-616
The formation mechanisms of garnet-like Li7La3Zr2O12 (LLZO) phase using LiOH?H2O as raw materials are investigated symmetrically by XRD and DTA/TG measurements. It was found that reaction mechanisms of the LLZO formation are as follows:
7Li2O 3La2O3 4ZrO2=2Li7La3Zr2O12
The production of LLZO phase takes place at about 680oC observed from the XRD patterns, in agreement with the thermic peak at 700oC in DTA/TG curves, which arises from the formation of LZZO phase. The stable existence temperature range of LLZO phase is wide, from 720 to 1000oC. However, LLZO is thermally unstable at the high temperatures (>1000oC) due to a serious loss of lithium element, and it discomposes into pyrochlore phase La2Zr2O7. And the amount of the decomposed products increased, and LLZO decreased gradually with the increase of the calcination temperature. When the reactant mixture was calcined at the low temperature, the produced phases were identified to be lanthanum compounds because La2O3 absorbs moisture and CO2 very easily. The chemical reactions at lower temperature are mainly related with the reactions among lanthanum compounds. LLZO powder was synthesized by solid state reaction at 800℃. It is found that the LLZO crystal belongs to the tetragonal symmetry. SEM observations show that the obtained LLZO powder was nano-sized. 相似文献
8.
利用混合定则和参照Zum-Gahr 模型、Khruschov 模型, 建立了一种连续网络结构增强金属基复合材料的抗压强度模型, 并进一步对模型进行了修正。通过压力和负压浸渗技术制备了不同增强相体积分数的复合材料, 测试了其抗压强度值, 将试验数据与模型进行了拟合, 数据基本在模型限定范围内。形成的相互贯穿、相互缠绕的网络结构增强复合材料的抗压强度与增强相的体积分数在上限时呈线性关系, 且随体积分数的增加而增加; 在下限时呈非线性关系, 当增强相体积分数超过80 %以上时, 抗压强度明显增加。与基体相比, 复合材料的抗压强度有明显提高。 相似文献
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采用真空扩散焊技术对Mg/Al异种材料进行了焊接。采用金相显微镜、扫描电镜(SEM)、显微硬度计及X射线衍射(XRD)对扩散界面附近的显微组织及性能进行了试验研究。试验结果表明,Mg/Al异种材料真空扩散焊在加热温度Tp=450-490℃,压力强度P=0.08-0.10MPa,保温时间t=40-60min时能得到良好的扩散焊接头。扩散焊界面过渡区形成了致密的新相化合物层,断口形貌呈粗糙暗灰色,以解理断裂为主并伴有脆性的混合型断口,扩散界面过渡区生成了MgAl、Mg3Al2、Mg2Al3等金属间化合物。 相似文献