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. 2023 Apr 18;16(8):3188.
doi: 10.3390/ma16083188.

Modeling of Severe Plastic Deformation by HSHPT of As-Cast Ti-Nb-Zr-Ta-Fe-O Gum Alloy for Orthopedic Implant

Dan Cătălin Bîrsan  1 , Carmela Gurău  1 , Florin-Bogdan Marin  1 , Cristian Stefănescu  1 , Gheorghe Gurău  1
Affiliations

Modeling of Severe Plastic Deformation by HSHPT of As-Cast Ti-Nb-Zr-Ta-Fe-O Gum Alloy for Orthopedic Implant

Dan Cătălin Bîrsan et al. Materials (Basel). .

Abstract

The High Speed High Pressure Torsion (HSHPT) is the severe plastic deformation method (SPD) designed for the grain refinement of hard-to-deform alloys, and it is able to produce large, rotationally complex shells. In this paper, the new bulk nanostructured Ti-Nb-Zr-Ta-Fe-O Gum metal was investigated using HSHPT. The biomaterial in the as-cast state was simultaneously compressed up to 1 GPa and torsion was applied with friction at a temperature that rose as a pulse in less than 15 s. The interaction between the compression, the torsion, and the intense friction that generates heat requires accurate 3D finite element simulation. Simufact Forming was employed to simulate severe plastic deformation of a shell blank for orthopedic implants using the advancing Patran Tetra elements and adaptable global meshing. The simulation was conducted by applying to the lower anvil a displacement of 4.2 mm in the z-direction and applying a rotational speed of 900 rpm to the upper anvil. The calculations show that the HSHPT accumulated a large plastic deformation strain in a very short time, leading to the desired shape and grain refinement.

Keywords: FEA; HSHPT; gum alloy; orthopedic implant; severe plastic deformation.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Processing of the blanks by High Speed High Pressure Torsion. (a,b) HSHPT scheme, (c,d) compression staples blank, (e) HSHPT tools, (f) HSHPT experimental setup.
Figure 2
Figure 2
Simulation bodies: (a) upper punch geometry, (b) 3D upper punch, (c) active part of upper punch, (d) sample, (e) lower punch.
Figure 3
Figure 3
Flow stress for different temperatures.
Figure 4
Figure 4
Force variation in the HSHPT process. (a) FEA, (b) experimental for disk-shaped workpiece.
Figure 5
Figure 5
HSHPT experimental parameters.
Figure 6
Figure 6
Pressure field: (a) at 2.6 s from the SPD beginning and (b) at 8 s from the SPD beginning.
Figure 7
Figure 7
Temperature profile at two moments in time, 6 s (a) and 8 s (b) from the SPD beginning.
Figure 8
Figure 8
Von Mises stress distribution: (a) on the upper surface of the workpiece at the time interval between 0 and 1 s, (b) on the upper surface of the workpiece between 1 s and 8 s of the HSHPT process, (c) Von Mises stress versus time in the points located on the upper surface of the workpiece, (d) Von Mises stresses at two moments of time, 6 s and 8 s.
Figure 9
Figure 9
HSHPT strain.
See this image and copyright information in PMC

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