Mechanical behavior of supersonic fine particle bombardment single crystal γ-TiAl alloys based on atomistic simulation: effects of velocity and crystal plane

Abstract The crystal orientation significantly affects the plastic deformation and mechanical properties of γ -TiAl alloys. However, there are few studies on the mechanical behavior of supersonic fine particle bombardment (SFPB) of single-crystal γ -TiAl alloys impacted with different crystal planes and velocities at the nanoscale. And the characterization of the mechanical properties in the presence of dislocation defects after impact is lacked. Therefore, in this paper, molecular dynamics is used to simulate the impact response and post-impact mechanical response of SFPB single-crystal γ -TiAl alloy. The results show that: at a certain impact velocity, the different ways of inducing dislocation slip due to the number of slip system initiations under crystal anisotropy lead to a smaller depth of subsurface damage on the (001) crystallographic plane compared to the other crystallographic planes; moreover, the yield strength and Young’s modulus of the (111) and (1 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mover> <mml:mn>1</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> </mml:mrow> </mml:mrow> </mml:math> 0) crystallographic planes are the largest after the impact, respectively. Under the same crystal plane, the subsurface damage depths of all crystal planes decrease with the increase of impact velocity; the yield strength of the (111) crystal plane of γ -TiAl alloy gradually increases, the yield strength of the (001) and (1 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mrow> <mml:mover> <mml:mn>1</mml:mn> <mml:mo stretchy="false">¯</mml:mo> </mml:mover> </mml:mrow> </mml:mrow> </mml:math> 0) crystal planes decreases, and the modulus of elasticity of the (001) and (111) crystal planes after impact is less sensitive to velocity. The angle between the two slip surfaces formed by the L-C dislocation during impact is 70.24°, while the angle between the two slip surfaces formed by the Hirth dislocation is 109.76°. This will provide atomic-scale deformation details of the plastic deformation and mechanical response of single-crystal γ -TiAl alloys bombarded by supersonic fine particles.