Effect of Microstructure on the Dimensional Stability of Extruded Pure Aluminum

Abstract

High-performance extruded aluminum alloys with complex textures suffer significant dimension variation under environmental temperature fluctuations, dramatically decreasing the precision of navigation systems. This research mainly focuses on the effect of the texture of extruded pure aluminum on its dimensional stability after various annealing processes. The result reveals that a significant increment in the area fraction of recrystallized grains with <100> orientation and a decrement in the area fraction of grains with <111> orientation were found with increasing annealing temperature. Moreover, with the annealing temperature increasing from 150 °C to 400 °C, the residual plastic strain after twelve thermal cycles with a temperature range of 120 °C was changed from −1.6 × 10−5 to −4.5 × 10−5. The large amount of equiaxed grains with <100> orientation was formed in the microstructure of the extruded pure aluminum and the average grain size was decreased during thermal cycling. The area fraction of grain with <100> crystallographic orientation of the sample annealed at 400 °C after thermal cycling was 30.9% higher than annealed at 350 °C (23.7%) or at 150 °C (18.7%). It is attributed to the increase in the proportion of recrystallization grains with <100> direction as the annealing temperature increases, provided more nucleation sites for the formation of fine equiaxed grains with <100> orientation. The main orientation of the texture was rotated from parallel to <111> to parallel to <100> after thermal cycling. The change in the orientation of grains contributed to a change in interplanar spacing, which explains the change in the dimension along the extrusion direction during thermal cycling.

Hot Deformation Behavior and Microstructure Evolution of a Novel Al-Zn-Mg-Li-Cu Alloy

“…The reason for the inclusion of the Cu element is that part of the Cu element is dissolved in the phase precipitation process [ 34 ]. From Figure 4 c,d, the interplanar spacing of the (111) plane for the α-Al is 0.2357 nm, which is close to the value of 0.234 nm of the pure Al [ 39 ]. The reason for this difference may be the result of lattice distortion of the complex composition.…”

Effect of Lattice Constants and Precipitates on the Dimensional Stability of Rolled 2024Al during Isothermal Aging

“…Fu et al studied the reasons for the reduction in the dimensional stability of high-performance extruded pure aluminum after annealing under thermal cycling. They found that the texture after annealing under thermal cycling rotated from parallel <111> to parallel <100> along the extrusion direction, and the change in grain direction led to the change in plane spacing, which further affected the dimensional stability of high performance extruded pure aluminum after annealing [ 15 ]. Dong et al studied the influence of quenching speed on the microstructure, residual stress, and dimensional stability of the Al–Cu–Mg–Si alloy.…”