Nickel-based alloy metal matrix composite (NAMMC) is a new type of composite material which is expected to replace traditional Nickel-base superalloy used in the manufacture of important hot-end components in aerospace, naval ships and industrial gas turbine engines due to its excellent high temperature strength, superior thermal fatigue resistance, high oxidation resistance and thermal corrosion resistance. However, these outstanding properties make it hard to process these materials with conventional manufacturing methods such as forging and machining owing to posing problems of high cost and energy consumptions. Laser additive manufacturing (AM) with a high degree of machining freedom and a high-energy-density laser beam as heat source has been used for processing NAMMC hot-end components with superior performance and complicated structure. Nevertheless, some manufacturing defects of poor bonding, high residual stress, cracking, pore etc. still exist in laser AM NAMMC parts. Therefore, this paper reviews research progress of laser AM NAMMC at present. The control method of manufacturing defect and the effect of reinforcements on the microstructure and mechanical properties of NAMMC are summarized. In addition, the challenges and prospects of laser AM NAMMC in the future are also discussed.

The effect of volume energy density and deposition energy density on the roughness, porosity, density and hardness of laser beam powder bed fusion (LBPBF) GTD222 Ni-based superalloy was systematically studied. The results showed that the roughness and porosity of the alloy decreased with the increase of the two laser energy densities, while the density and hardness increased. When the volume energy density and the deposition energy density exceeded a threshold value, the density and hardness reached the maximum value and almost remained constant. The volume energy density could be used to estimate the laser conditions for obtaining high-density LBPBF GTD222 alloy more accurately than the deposition energy density. The process parameters for the transformation of the alloy from porous to dense were determined based on the volume energy density. This study provides guidance for the optimization of the process parameters of LBPBF GTD222 alloy.