Approach to In-Situ Producing Reinforcing Phase Within an Active-Transient Liquid Phase Bond Seam for Aluminum Matrix Composite

Active-Transient Liquid Phase (A-TLP) Bonding of Pure Aluminum Matrix Composite Reinforced with Short Alumina Fiber Using Al-12Si-xTi Foils as Active Interlayer

“…The results suggested that Ti was hard to diffuse into Al matrix, and then excessive Ti tended to form aluminide in bond seam, because (I) Ti has little solubility in Al [55] and (II) Ti is a melting point increaser (MPI) for Al rather than a MPD. [47,48] 2. Final microstructure under high pressure Figure 4 shows the final microstructure using different interlayers of Al-12Si-xTi (x = 0, 0.1, 0.5, and 1 in wt pct) under high pressure of 1 MPa at 883 K (610°C) for 30 minutes.…”

“…[46] For a low-volume-fraction SiC particle (10 vol pct)-reinforced A356 composite, it was found that Al-Cu-Ti ternary active interlayer can wet both A356 matrix and SiC particle, and it can produce a reinforcing phase of in situ small and dispersive Al-Si-Ti intermetallic phase within the TLP bond seam. [47] For a medium-volume-fraction short alumina fiber (30 vol pct)-reinforced pure Al composite, in our previous study evaluating the wettability using the sessile drop method, [48] it was found that the Al-12Si-1Ti active filler metal penetrated in situ into the composite substrate faster and covered Al 2 O 3 short fiber closely, and a bare Al 2 O 3 short fiber was difficult to observe on the substrate surface. For the common Al-12Si brazing filler metal, the interfacial gaps at the R/M interface could not be eliminated due to poor wettability.…”

Availability of in-situ reinforced active-transient liquid phase bond with good wettability for 70 vol.% SiCp/A356 composite using Al-Mg-Ga-Ti interlayer

“…The presence and refinement of the in-situ precipitated Ti-containing IMC particulate phase only when the braze was in just fully melting state (500 o C) can be analysed as follows. According to the model of in-situ reinforcement formation within TLP bond seam during isothermal solidification just for MPI-containing interlayer, which was proposed by Zhang et al (the current author) [20], the presence of the precipitated Ti-containing IMC phase should result from the concentration-precipitation-termination-engulfment cycle, namely when local concentration of liquid MPI (Ti) at isothermally solidified front increases to a critical value with the movement of liquid-solid interface during isothermal solidification, an Al-MPI IMC would be precipitated. While MPI-free interlayer is unable to uniformly distribute IMC because liquid MPD (an eutectic former) would be pushed towards bond center by isothermally solidified front, leading to the absence of precipitation of Al-MPD IMC in the early formed isothermal solidified region of solid-solution matrix.…”

“…This manuscript version is made available under the Elsevier user license http://www.elsevier.com/open-access/userlicense/1.0/ were recommended. To improve the wettability at P/M interface, mechanical route (introducing ultrasonic vibration by Yan and Xu [12][13][14][15][16][17][18]) and metallurgical route (adding active element by the present authors [19][20][21][22][23]) were reported. The TLP bonding process for Al-MMCs using an interlayer containing the active element capable of reacting with ceramic reinforcement, e.g., Ti, is called active-transient liquid phase bonding (A-TLP) by the current author [19][20][21][22][23].…”

“…To obtain fine, dispersive, stable and refractory intermetallic compound (IMC) as in-situ reinforcing phases in TLP bond seam, the current authors proposed that melting point increaser (MPI), which must have a higher melting point than Al and has no eutectic reaction with Al (e.g., Ti or Zr), should be added into interlayer together with MPD via uniform precipitation of Al-MPI IMC phase during isothermal solidification, and succeeded in achieving fine Al-Si-Ti IMC phase as in-situ reinforcement for TLP bond seam for 10 vol. % SiCp/A356 composite using Al-Cu-Ti braze foil [20].…”