Effects of Multi-directional Forging Temperature on Microstructure and Mechanical Properties of 2219 Al Alloy

doi:10.3901/JME.2023.22.275

Abstract

Abstract: During the manufacturing process of 2219 Al alloy launch vehicles tank transition ring, the severe segregation of residual crystalline phase(RCPs) is the main factor leading to uneven microstructure and low mechanical properties(MPs) of the rings, which urgently needs to be resolved. Multi-directional forging tests on 2219 Al alloy ingots are carried out. The effects of multi-directional forging temperature(T) on RCPs and mechanical properties are investigated. The results show that with the increase of T (from 240 ℃ to 450 ℃), the area fraction(f) of RCPs is found to increase, but the value of f decreases sharply when T increases to 510 ℃. Moreover, when T is 450 ℃, RCPs show poor reduction effect, and the fracture structure of the alloy is dominated by transgranular fracture with obvious brittle fracture characteristics, so the alloy show low MPs and the tensile strength σ_b, yield strength σ_s, and elongation e of the alloy are only 381 MPa, 298 MPa, and 5.9%, respectively. However, when T increases to 510 ℃, RCPs is refined by stretching and dissolving, and the transgranular fracture is still the main fracture mode but the brittle fracture is changed to ductile fracture, so the MPs is improved and the values of σ_b,σ_s, and e are 398 MPa, 328 MPa, and 7.7%, respectively. When T is 240 ℃, RCPs is refined by crushing and show high degree of reduction; in additional, the fracture structure is a mixed mode of intergranular and transgranular fracture, which show obvious plastic fracture characteristics; so the optimal MPs is obtained and the values of σ_b,σ_s, and e are 417 MPa, 326 MPa, and 8.2%, respectively.

Key words: 2219 Al alloy, multi-directional forging temperature, residual crystalline phase, reduction, mechanical properties

CLC Number:

TB31

MAO Xianchang, YI Youping, HUANG Shiquan, HE Hailin. Effects of Multi-directional Forging Temperature on Microstructure and Mechanical Properties of 2219 Al Alloy[J]. Journal of Mechanical Engineering, 2023, 59(22): 275-286.

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