| Popis: |
Laser assisted additive manufacturing (LAAM) has been employed in many ways to produce metallic structures, performing repairs of difficult to manage parts and applying metallic coatings for improved surface properties or to generate highly improved composite metallic surfaces. Out of different LAAM techniques, those involving spraying of metallic powder into a focussed laser beam have significantly contributed in operations for repair of damaged expensive parts with typical contours and profile features. Some efforts have also been made to use these technologies to produce lattice and composite structures or graded metallic parts with improved properties. All laser generated depositions, be it coating or complete parts, demand thorough mechanical characterization to ensure the absence of microporosity, homogeneity of microstructure, mechanical strength under applied loads and consistency of performance under wear. This article undertakes a detailed review of research conducted to determine the mechanical properties of laser generated high strength alloy structures produced mainly by powder deposition techniques. This wide-ranging study spanning over different aspects of mechanical characterization and alloy types will highlight the significant and increasingly important contributions of powder deposited laser-based manufacturing in performing customized manufacturing jobs. There are still many performance gaps which demand further research and development. These include producing overhang structures, control of surface roughness in inclined planes and minimizing thickness variations with increasing heights. Improvements in these frontiers will eventually determine the role of laser assisted powder deposition technologies within the domain of LAAM. It will also assess whether these processes can become an efficient and reliable system for producing customized, high strength parts with greater choice of combining different metals or will be limited to only repair and coating applications and manufacturing of structures with prismatic sections. |
