Method for preparing TiAl+Ti2AlNb composite materials by laser melting deposition

Abstract

The invention belongs to the technical field of laser added material manufacturing, and relates to a method for preparing TiAl+Ti2AlNb composite materials by laser melting deposition. The laser melting deposition method is adopted to form the TiAl+Ti2AlNb composite materials; and the feeding quantity of Ti2AlNb is adjusted to achieve a pinning effect in composite material structures to improve overall plasticity of the materials. Meanwhile, circular samples are formed, and scanning paths are changed to concentric arcs to prevent the tensile stress of linear scanning paths of rectangular samples; and concentric circle openings on each layer are converted by 60-90 degrees, that is, the positions of scanning initial points on each layer are changed, so that the thermal stress concentration isreduced to prevent cracks. The heat input quantity in the forming process is controlled, and the substrate preheating temperature in the forming process is adjusted to slow down the formed metal solidification speed and cooling speed, so that the stress is released for a longer time.

Description

technical field [0001] The invention belongs to the technical field of laser additive manufacturing and relates to a TiAl+Ti 2 A method for preparing AlNb composite materials by laser melting deposition. Background technique [0002] Laser melting deposition is a new type of additive manufacturing technology, which has great advantages in the fields of new materials, new structure development, complex structure manufacturing and load-bearing component repair, so it is widely used in aviation, aerospace and biology and other fields. The density of TiAl-based alloy is low, about 3.9g / cm 3 , its creep resistance and high-temperature oxidation resistance are far superior to high-temperature titanium alloys, comparable to nickel-based superalloys, and have high specific stiffness, specific strength and thermal conductivity. However, the low symmetry of the matrix γ-TiAl phase due to its directional strong bonding and deformation behavior based on the ordered structure also lead...

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Problems solved by technology

[0003] However, with the laser melting deposition method, the cooling rate during the forming process is faster, and the stress is not easy to release, which causes crack defects (see figure 1 )

The crack defects in the laser melting deposition forming sample have an impact on the subsequent microstructure and performance analysis, and it is impossible to measure its high-temperature mechanical properties at room temperature. 2 Plasticizing Mechanism of AlNb on TiAl-Based Alloys

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