...
首页> 外文期刊>Metallurgical and Materials Transactions, A. Physical Metallurgy and Materials Science >Laser Cladding of Quasi-Crystal-Forming Al-Cu-Fe-Bi on an Al-Si Alloy Substrate
【24h】

Laser Cladding of Quasi-Crystal-Forming Al-Cu-Fe-Bi on an Al-Si Alloy Substrate

机译:Al-Si合金基底上准晶体形成的Al-Cu-Fe-Bi的激光熔覆

获取原文
获取原文并翻译 | 示例
   

获取外文期刊封面封底 >>

       

摘要

We report here the results of an investigation aimed at producing coatings containing phases closely related to the quasi-crystalline phase with dispersions of soft Bi particles using an Al-Cu-Fe-Bi elemental powder mixture on Al-10.5 at. pet Si substrates. A two-step process of cladding followed by remelting is used to fine-tune the alloying, phase distribution, and microstructure. A powder mix of Al_(64)Cu_(22.3)Fe_(11.7)Bi_2 has been used to form the clads. The basic reason for choosing Bi lies in the fact that it is immiscible with each of the constituent elements. Therefore, it is expected that Bi will solidify in the form of dispersoids during the rapid solidification. A detailed microstructural analysis has been carried out by using the backscattered imaging mode in a scanning electron microscope (SEM) and transmission electron microscope (TEM). The microstructural features are described in terms of layers of different phases. Contrary to our expectation, the quasi-crystalline phase could not form on the Al-Si substrate. The bottom of the clad and remelted layers shows the regrowth of aluminum. The formation of phases such as blocky hexagonal Al-Fe-Si and a ternary eutectic (Al + CuAl_2 + Si) have been found in this layer. The middle layer shows the formation of long plate-shaped Al_(13)Fe_4 along with hexagonal Al-Fe-Si phase growing at the periphery of the former. The formation of metastable Al-Al_6Fe eutectic has also been found in this layer. The top layer, in the case of the as-clad track, shows the presence of plate-shaped Ali3Fe4 along with a 1/1 cubic rational approximant of a quasi-crystal. The top layer of the remelted track shows the presence of a significant amount of a 1/1 cubic rational approximant. In addition, the as-clad and remelted microstructures show a fine-scale dispersion of Bi particles of different sizes formed during monotectic solidification. The remelting is found to have a strong effect on the size and distribution of Bi particles. The dry-sliding wear properties of the samples show the improvement of wear properties for Bi-containing clads. The best tribological properties are observed in the as-clad state, and remelting deteriorates the wear properties. The low coefficient of friction of the as-clad and remelted track is due to the presence of approximant phases. There is evidence of severe subsurface deformation during the wear process leading to cracking of hard phases and a change in the size and shape of soft Bi particles. Using these observations, we have rationalized possible wear mechanisms in the Bi-containing surface-alloyed layers.
机译:我们在这里报告了一项调查结果,该调查结果旨在使用在Al-10.5 at上的Al-Cu-Fe-Bi元素粉末混合物,生产包含与准晶体相密切相关的相的相,该相与软Bi颗粒的分散体有关。宠物硅基板。熔覆和重熔的两步过程用于微调合金,相分布和微观结构。 Al_(64)Cu_(22.3)Fe_(11.7)Bi_2的粉末混合物已用于形成包层。选择Bi的基本原因在于它与每个组成元素都不互溶。因此,期望Bi在快速凝固期间将以分散体的形式凝固。通过在扫描电子显微镜(SEM)和透射电子显微镜(TEM)中使用反向散射成像模式进行了详细的微观结构分析。根据不同相的层描述了微观结构特征。与我们的预期相反,在Al-Si衬底上无法形成准晶相。覆层和重熔层的底部显示了铝的再生长。在该层中发现了诸如块状六方Al-Fe-Si和三元共晶(Al + CuAl_2 + Si)的相的形成。中间层显示出长板状的Al_(13)Fe_4的形成,并在前者的外围生长出六角形的Al-Fe-Si相。在该层中还发现了亚稳态的Al-Al_6Fe共晶的形成。在包层轨迹的情况下,顶层显示出存在板状Ali3Fe4以及准晶体的1/1立方有理近似值。重熔轨迹的顶层显示出大量的1/1立方有理近似值。另外,包层和重新熔化的微结构显示出在单晶凝固过程中形成的不同尺寸的Bi颗粒的细微分散。发现重熔对Bi颗粒的尺寸和分布具有强烈影响。样品的干滑磨损性能显示了含Bi包层的磨损性能得到改善。在包层状态下观察到最佳的摩擦学性能,重熔会使磨损性能恶化。包覆和重熔轨迹的摩擦系数低是由于存在近似相。有证据表明,在磨损过程中,严重的地下变形会导致硬质相的破裂以及软Bi颗粒的尺寸和形状发生变化。利用这些观察,我们合理化了含Bi的表面合金层中可能的磨损机理。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱:kefu@zhangqiaokeyan.com

京公网安备:11010802029741号 ICP备案号:京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有
  • 客服微信

  • 服务号