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排序方式: 共有3400条查询结果,搜索用时 78 毫秒
61.
铝锂合金的合金化与微观组织演化 总被引:3,自引:0,他引:3
评述了铝锂合金的发展历程和应用以及我国铝锂合金研究所取得的成果。阐述了第3代铝锂合金的成分、微观组织和性能特点,讨论了合金化元素在调控铝锂合金微观组织进而改善性能方面的作用。大量研究表明,这些合金化元素可改变铝锂合金中原有析出相的大小、形状、分布,或刺激新强化相的析出,也可以细化晶粒、控制再结晶和晶粒取向。时效析出过程的本质和动力学在很大程度上取决于合金化元素之间的交互作用和合金原子的团簇化过程。 相似文献
62.
概述高电位Mg-Mn牺牲阳极组织、电化学性能特点以及应用,分析杂质元素Ca、Sr、Mn元素和熔铸新工艺对高电位镁阳极组织和电化学性能的影响、Zn含量对Mg-zn超高电位镁阳极电化学性能的影响,挤压高电位镁阳极的生产工艺及应用,指出高电位镁阳极存在的问题并对其发展趋势进行展望。 相似文献
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64.
AISI304不锈钢表面渗Cu层对其摩擦学行为的影响 总被引:2,自引:0,他引:2
利用等离子表面合金化技术,在304不锈钢表面制备渗Cu改性层。借助球-盘磨损试验机对改性层常规大气环境下与不同偶件(GCr15球,Al2O3球)对摩时的摩擦学性能进行了测试。结果表明:不锈钢表面渗Cu改性层均匀致密、与基体结合良好,厚度大约26μm,主要由纯Cu和膨胀的奥氏体等相组成。渗Cu改性层的摩擦学性能与摩擦偶件相关。渗Cu不锈钢与GCr15球对摩时Cu改性层阻止了不锈钢与配副直接接触,并在摩擦过程中起到固体润滑作用,明显改善了不锈钢的摩擦学性能;渗Cu不锈钢与Al2O3球对摩时,由于陶瓷球的稳定化学性能及Cu改性层相对较低的剪切强度,导致摩擦过程中磨粒磨损加剧。 相似文献
65.
The influences of minor scandium and zirconium combination alloying on the as-cast microstructure and mechanical properties of Al-4Cu-1.5Mg alloy have been experimentally investigated.The experimental results show that when the minor elements of scandium and zirconium are simultaneously added into the Al-4Cu-1.5Mg alloy,the as-cast microstructure of the alloy is effectively modified and the grains of the alloy are greatly refined.The coarse dendrites in the microstructure of the alloy without Sc and Zr additions are refined to the uniform and fine equiaxed grains.As the additions of Sc and Zr are 0.4% and 0.2%,respectively,the tensile strength,yield strength and elongation of the alloy are relatively better,which are 275.0 MPa,176.0 MPa and 8.0% respectively.The tensile strength is increased by 55.3%,and the elongation is nearly raised three times,compared with those of the alloy without Sc and Zr additions. 相似文献
66.
In this study, composites containing pure magnesium and hybrid reinforcements (5.6 wt.% titanium (Ti) particulates and 2.5 wt.% nanoscale alumina (n-Al2O3) particles) were synthesized using the disintegrated melt deposition technique followed by hot extrusion. The hybrid reinforcement addition into the Mg matrix was carried out in two ways: (i) by direct addition of the reinforcements into the Mg-matrix, Mg-(5.6Ti + 2.5n-Al2O3) and (ii) by pre-synthesizing the composite reinforcement by ball milling and its subsequent addition into the Mg-matrix, Mg-(5.6Ti + 2.5n-Al2O3)BM. Microstructural characterization revealed significant grain refinement due to reinforcement addition. The evaluation of mechanical properties indicated a significant improvement in microhardness, tensile and compressive properties of the composites when compared to monolithic magnesium. For the Mg-(5.6Ti + 2.5n-Al2O3) composite, wherein the reinforcements were directly added into the matrix, the improvement in strength properties occurred at the expense of ductility. For the Mg-(5.6Ti + 2.5n-Al2O3)BM composites with pre-synthesized ball-milled reinforcements, the increase in strength properties was accompanied by an increase/retention of ductility. The observed difference in behaviour of the composites is primarily attributed to the morphology and distribution of the reinforcements obtained due to the ball-milling process, thereby resulting in composites with enhanced toughness. 相似文献
67.
Production of bulk Al-TiB2 nanocomposite from mechanically alloyed powder was studied. Al-20 wt.% TiB2 metal matrix nanocomposite powder was obtained by mechanical alloying (MA) of pure Ti, B and Al powder mixture. A double step process was used to prevent the formation of undesirable phases like Al3Ti intermetallic compound, which has been described in our previous papers. The resultant powder was consolidated by spark plasma sintering (SPS) followed up by hot extrusion. The structural characteristics of powder particles and sintered samples were studied by X-ray diffractometry (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Hardness measurements were conducted on the cross section of powder particles and sintered sample and the tensile behavior of extruded samples was evaluated. The results showed that the prepared Al-20 wt.% TiB2 nanocomposite has good thermal stability against grain growth and particle coarsening. Extruded Al-20 wt.% TiB2 showed a hardness value of 180 VHN and yield and tensile strength of 480 and 540 MPa, respectively, which are much higher than those reported for similar composites made by other processes. 相似文献
68.
69.
激光熔覆所用粉末材料的制备方法主要是雾化法。为探索激光熔覆专用材料的制备新方法,将以单元素粉末的形式,按照19Cr-14Ni不锈钢的成分来配制混合粉,并将该混合粉机械合金化45h,在45#钢板上分别将采用上述两种不锈钢粉末进行激光熔覆。采用X射线衍射(XRD)、扫描电镜(SEM)/能谱仪(EDS)、腐蚀电化学等方法研究熔覆层的相组成、微结构和耐蚀性。结果表明,与雾化粉体激光熔覆层相比,机械合金化粉体激光熔覆层的枝晶得到细化,其组织呈连续网状分布,Cr元素的枝晶间偏析得以改善;与雾化粉体相比,机械合金化能提高粉体熔覆层的耐蚀性能,但其硬度略有降低。 相似文献
70.