Influence of Si content on interfacial reactions and mechanical properties of dual-spot laser welded-brazed Ti/Al joints. (August 2020)

• Record Type: Journal Article
• Authors: Li, Peng; Lei, Zhenglong; Zhang, Xinrui; Chen, Yanbin
• Is Part Of: Journal of manufacturing processes. Volume 56:Part A(2020)
• Page Start: 950
• Page End: 966
• Publication Date: 2020-08
• Subjects: Laser welded-brazed -- Si content -- Intermetallic compound -- Formation mechanism -- Fracture load; Production management -- Data processing -- Periodicals; Manufacturing processes -- Periodicals; Procestechnologie; Productietechniek; Production -- Gestion -- Informatique -- Périodiques; Fabrication -- Périodiques; Manufacturing processes; Production management -- Data processing; Periodicals; 670.5
• DOI: 10.1016/j.jmapro.2020.06.001
• Languages: English
• ISSNs: 1526-6125

Abstract

Graphical abstract: Highlights: The addition of Si in wires decreased the thickness of interfacial intermetallic compound layer in Ti/Al joint. The thermodynamic calculation was conducted to explain elemental diffusion behavior at interface. The formation mechanism of nano-granular Ti5 Si3 and Ti7 Al5 Si12 at interface was revealed. The effect of Si content on mechanical properties of joints was investigated. Abstract: Pure-Al, Al-5Si, and Al-12Si were selected as filler materials in dual-spot laser welded-brazed Ti/Al joints to investigate the influence of Si content on interfacial reactions and mechanical properties. The microscale and nanoscale structures of the interfacial intermetallic compound (IMC) were analyzed by transmission electron microscopy (TEM). The IMC phase at the brazing interface in joints with pure-Al was only TiAl3 with twin structure defects and stacking faults. Ti(Al, Si)3 and nano-granular Ti7 Al5 Si12, Ti5 Si3 phases were produced at brazing interfaces in joints with Al-5Si and Al-12Si. There were orientation relationships (OR) between Ti7 Al5 Si12 and Ti(Al, Si)3, Ti5 Si3 and Ti7 Al5 Si12 . The interfacial reactions were clarified using TEM images and thermodynamic calculations. The formation mechanism of nano-granular phases in joints with Al-5Si and Al-12Si was determined to proceed via a mechanism that included direct reactions and precipitation. The chemical potential of Si ( μSi ) decreased as the Ti content increased, resulting in the aggregation of Si atoms at the brazing interface. The fracture load of joint was improved by the addition of Si element in filler metal.