铝合金表面激光熔覆Fe-Al青铜过渡区的组织结构及其在小能多冲作用下的行为

Microstructure and Multiple-Impact Response of the Transition Region Between a Laser-Clad Fe-Al Bronze Coating and Its Aluminum Alloy Substrate

摘要:

研究了Al－Si合金表面激光熔覆Fe－Al青铜合金过渡区的组织和相结构；探讨了在小能量多冲作用下过渡区的行为。结果表明：熔覆层／基材间过渡区的组织和相结构存在一定的层次，靠近熔覆层的一侧为不均匀的块状Cu9Al4＋Cu3Al；中间区为块状Cu9Al4＋针状CuAl2；向基材靠近时，过渡区的针状CuAl2相逐渐减少，α-Al相逐渐增多。在小能多冲作用下，过渡区裂纹形成干脆性相CUAl2富集的区域，激光扫描速度对CUAl2相在过渡区的分布厚度影响显著，进而影响到过渡区的抗小能多冲行为。扫描速度在10mm／s～

Abstract:

The microstructure and small energy multi-impact (SEMI) behavior of the transition region between a laser-clad Fe-Albronze coating and its aluminum alloy substrate have been investigated. The results show that the transition region consists of severallayers. The layer adjacent to the clad region is composed of nonuniform block-like Cu9Al4 and Cu3Al phases. The middle layer is characterized by a mixed structure of block-like Cu3Al and needle-like CuAl2. In the layer near to the substrate the volume fractivn of needle-like CuAl, phase decreases and volume fraction of a-Al phase increases when approaching to the substrate. Under SEMI loading,cracks initiate in the CuAl2, phase-rich region. Laser scanning velocity has a significant influence on the volume fraction of CuAl,phase, and thus directly affects the SEMI resistance of the transition region. The laser-clad bronze coatings produced at a scanningvefority of 10mm/s to 14 mm/s has better resistance to SEMI than those produced at higher scanning velocities.