Transient liquid phase bonding of aluminium alloy using two-step heating process

Abstract

5A02 aluminium alloy was joined by transient liquid phase (TLP) bonding using the two-step heating process as follows: the faying area was first heated to 600uC and kept for 5 s and then cooled down to 595uC and kept for 3 min. The microstructure and properties of the joint were investigated and compared with that of conventional TLP bond at 595uC for 3 min. The results show that the two-step heating process can produce a wave bond line that is different from the planar interface associated with conventional TLP bonding at a constant temperature. The defects at the bond line are greatly reduced, and metal to metal contacts are established along the wave bond line using the two-step heating process. Therefore, the tensile strength and bending ductility of the joint are dramatically improved.

Transient liquid phase diffusion bonding of Al/Al2O3 nanostructured metal matrix composites

“…11, 12 Transient liquid phase (TLP) bonding is based on the principle that isothermal solidification takes place after diffusion of a high melting material into a melted, low melting material and the simultaneous formation of high melting intermetallic phases. 6, 10 The diffusion soldering process is based on the diffusion phenomena between the different metallic materials of the soldering systems, which are used in form of layers. First, solid–liquid diffusion occurs on the surface of the layers until a eutectic position is reached.…”

“…The lower temperature limit of 550°C was selected to be above the Al–Cu eutectic temperature of 548°C. 5, 10 The samples were heated to the joining temperature at a rate of 65°C min −1 . Having been held at desire temperature for 10, 20 and 30 min, the power was turned off and the samples were cooled to room temperature in the vacuum as the bonding process was completed.…”

Microstructural Evolution in Nonvacuum Solid-State Diffusion Bonded Joints of AA2219

“…While joining the diferent metal alloys, the diferences in physical and thermal properties would become the main hurdles [7][8][9]. Te major difculty in joining aluminium and its alloys by conventional and even advanced welding techniques is the tenacious oxide flm that exists on the faying surfaces, acting as a strong barrier for atomic interdifusion [10,11]. Tough the welding properties of the AA2219 are superior to those of other aluminium alloys, the welded joints exhibit poor strength even when using advanced welding techniques such as gas metal arc welding (GMAW), gas tungsten arc welding (GTAW), and plasma arc welding (PAW).…”

Effect of Post-Weld Heat Treatment on the Solid-State Diffusion Bonding of 6061 Aluminum Alloy

“…However, common filler metals, such as BAlSi-4 and Al-12Si alloys, exhibit high brazing temperatures (above 566 • C) that are close to or above the melting points of some aluminum alloys [10,11], leading to the risk of joint degradation. Some lowtemperature filler metals and the transient liquid phase (TLP) bonding technique have been adopted to address this issue [12,13], and bonding materials such as Cu, Ag, and Mg, which are melting point depressants that form eutectics or intermetallic compounds (IMCs) with Al alloy, have been developed to avoid the risk of melting the base material. For example, silver and copper-based filler metal [14] and Cu or Ag foils as interlayers [12,13,15,16] that form Al-Cu or Al-Ag IMCs at the interface have been utilized to provide sound interfaces.…”

“…Some lowtemperature filler metals and the transient liquid phase (TLP) bonding technique have been adopted to address this issue [12,13], and bonding materials such as Cu, Ag, and Mg, which are melting point depressants that form eutectics or intermetallic compounds (IMCs) with Al alloy, have been developed to avoid the risk of melting the base material. For example, silver and copper-based filler metal [14] and Cu or Ag foils as interlayers [12,13,15,16] that form Al-Cu or Al-Ag IMCs at the interface have been utilized to provide sound interfaces. However, research showed that the failure and breakage of the joint usually initiated in the IMC phase and led to deterioration of the joint strength due to embrittlement [14,17].…”