Macro defects in direct laser deposition process

Currently, direct laser deposition technology is used to create products with complex geometry in various industries, such as: aircraft engine building, shipbuilding, and the energy industry. This technology allows made workpieces with minimal subsequent machining. Parts manufactured for these areas should have the required performance characteristics. The mechanical properties of products obtained using direct laser deposition technology are affected by internal and surface defects: pores, non-fusion, cracks, and roughness, since they are the main stress concentrators. This article describes such internal defects as pores and non-fusion in different situations, identifies the causes of their occurrence and considers their elimination methods. (C) 2019 Elsevier Ltd. All rights reserved.