Evaluation of Residual Stress Distribution and Relaxation on In Situ TiB2/7050 Al Composites

Abstract

Interior residual stresses induced by quenching may cause distortion during subsequent machining processes. Hence, various strategies have been employed to relieve the interior residual stress, such as stretching, post treatment, and other techniques. In this study, the stress distribution inside TiB2/7050 Al composite extrusions was investigated and the effects of different methods on relieving the quenching-induced stress were compared. Firstly, three TiB2/7050 Al composite extrusions were treated by stretching, stretching and heat treatment, and stretching and cold treatment processes, respectively. Then, the multiple-cut contour method was employed to assess the residual stresses in the three workpieces. Experimental results indicate that the interior stress of TiB2/7050 Al composite extrusions after stretching ranges from −89 MPa to +55 MPa, which is larger than that in 7050 aluminum alloy, which ranges from −25 Pa to +25 MPa. The heat treatment performs better than the cold treatment to reduce the post-stretching residual stress, with a reduction of 23.2–46.4% compared to 11.3–40.8%, respectively. From the stress map, it is found that the stress distribution after the heat treatment is more uniform compared with that after the cold treatment.

Analytical modeling of fatigue crack growth in plastically pre‐strained steels

“…Furthermore, Equation (25), considering the stress ratio effect, may be appropriately modified to also include the residual stresses effect in FCGR analysis. However, in the present analysis, the influence of residual stresses was not taken into account as the effect is expected to be insignificant due to the relaxation of residual stresses induced by the cutting procedure of the samples from the large, pre‐strained plate 67,68 …”

“…However, in the present analysis, the influence of residual stresses was not taken into account as the effect is expected to be insignificant due to the relaxation of residual stresses induced by the cutting procedure of the samples from the large, pre-strained plate. 67,68 The proposed fatigue crack growth equation has certain limitations in its current form as it can only be used for mode I fracture analysis and plane stress conditions specifically for thin sheets under uniaxial cyclic loading. The fixed value of the ΔΚ exponent (m = 4) in fatigue crack growth equation, which at a first glance seems to restrict its applicability to certain material systems, has been found in literature to be suitable for a wide range of ductile metallic alloys.…”

Effect of Extrusion Temperature on the Microstructure and Mechanical Properties of SiCnw/2024Al Composite

“…Recently, composites materials reinforced with nano-phases, such as ceramic nano-particles [1,2], carbonous nano-phase (CNT) [3,4] and graphene [5,6] have been widely explored. Besides the above phases, SiC nanowires are also very promising to be used as reinforcement materials [7,8].…”