The Determination of Residual Stress in Quenched and Cold-Compressed 7050 Aluminum Alloy T-Section Forgings by the Contour Method and Neutron Diffraction

• Published in: Journal of materials engineering and performance Vol. 27; no. 11; pp. 6049 - 6057
• Main Authors: Liu, Xiaolong, Wimpory, Robert C., Gong, Hai, Liu, Yuntao, Chen, Dongfeng, Liu, Yaoqiong, Wu, Yunxin, Li, Chen
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-11-2018
• Subjects: ALUMINIUM ALLOYS; BRAGG REFLECTION; Characterization and Evaluation of Materials; Chemistry and Materials Science; COMPARATIVE EVALUATIONS; COMPRESSION; Corrosion and Coatings; DEFORMATION; Engineering Design; FASTENING; FORGING; MATERIALS SCIENCE; NEUTRON DIFFRACTION; PRESSURE RANGE MEGA PA 100-1000; Quality Control; Reliability; RESIDUAL STRESSES; Safety and Risk; THICKNESS; Tribology; 7050 T-section forging; cold compression; residual stress; neutron diffraction; quenching; the contour method
• ISSN: 1059-9495; 1544-1024
• DOI: 10.1007/s11665-018-3676-0

Residual stresses were determined through the thickness of quenched and quenched followed by cold compression 7050 aluminum alloy T-section forgings using the contour method and neutron diffraction. 7050 T-section forgings are used for the manufacture of the connecting joints of wing and fuselage. Inevitably high residual stresses are introduced during the quenching process of 7050 T-section forgings, which could be reduced by cold compression to overcome the effect of residual stress on machining deformation. The longitudinal residual stresses obtained by the two techniques achieved good agreement in both trend and magnitude in both the quenched and quenched followed by cold compression 7050 T-section forgings. The stress-free lattice spacing of Al(311), the Bragg reflection used for the neutron measurements, was obtained from a 5-mm slice using the plane-stress condition, and its variation through the thickness is insignificant in both the quenched specimen and quenched followed by cold compression specimen. A comparison of the residual stresses in the quenched specimen and quenched followed by cold compression specimen showed significant changes in range of residual stresses from (− 304, 262 MPa) induced by quenching process to (− 125, 142 MPa) due to 3% cold compression. The percentage reduction in residual stress in the quenched specimen due to 3% cold compression was (46, 59%).