Dynamic softening mechanism of 30 % SiCp/2024Al composite during hot deformation process

Abstract

Using Gleeb‐1500D simulator, the isothermal compression tests of 30 % SiCp/2024Al (volume fraction) are conducted at a temperature range of 623 K ‐ 773 K and a strain rate range of 0.01 s‐1 ‐ 10 s‐1. The softening mechanism of composites during hot deformation has been proposed based on the Zener‐Hollomon parameter Z, deformation temperature T and microstructure analysis. Cross slip of dislocation plays a dominant role under the conditions of lnZ≥59.634 and T≤673 K. While, deformation mechanisms such as cross slip, climb of dislocation and unzipping of the three dimensional dislocation network play a joint role when lnZ≤61.933 and T≥623 K. Particularly, dynamic recrystallization occurred when lnZ≤55.669 and T≥723 K. The cross slip, climb and unzipping of dislocation and dynamic recrystallization are the main softening mechanisms. The role of the dynamic recrystallization mechanisms become more significant and the critical strain of dynamic recrystallization decrease with the decrease of lnZ. Dynamic recrystallization nucleation mechanisms are mainly constituted of the subgrain combination and the bulging of the grain boundary.

Effect of deformation temperature and degree on tensile properties of the extruded 2024Al/Al18B4O33w composite with extrusion – forging multistage hot deformation

“…Some cast defects like porosity and clusters of reinforcement, reduce the enhancement effect and limit the application. Various methods such as forging or extrusion are used to minimize porosity and improve the property of aluminum matrix composite [5][6][7].…”

Power dissipation efficiency and temperature sensitivity coefficient of 2024Al/Al18B4O33w composite deformed at strain rate up to 10.0 s−1

“…Whisker reinforced aluminum matrix composites have extended accepted in applications [1][2][3][4][5]. However, the addition of reinforcements increases the resistance to plastic deformation and then brings the risk of damage during hot forging.…”