Growth Kinetics of Intermetallic Phases in Transient Liquid Phase Bonding Process (TLPB) in Al /Ni System

Abstract

New processes and materials are vital nowadays, since specific features of materials are essential to accomplish the more demanding technological and environmental requirements. Al/Ni system has stimulated a large number of phase equilibrium, thermodynamic, diffusion and related studies. Its relevance relays on first principle features as well as technological importance.Transient Liquid Phase Bonding(TLPB) process is presented in this work due to the advantages of this method above others. Low temperatures of processing are needed, to obtain stable intermetallic phases (IPs) suitable for high temperatures of service. The aim of this research is to investigate the impact of temperature on the IPs growth and formation mechanisms, completing previous works on microstructure and kinetics characterization of IPs in Al/Ni system at 720°C. The results of SEM-EDS/WDS analyses of the cross-sections of the bonds showed the presence of Al3Ni and Al3Ni2at the beginning of the interaction between Al and Ni, which are consistent with the phase equilibrium diagram. The Al3Ni2layer growth showed linear correlation with time at 800°C, whereas at 900 and 1000°C it suggested a diffusive growth. Inert markers experiments allowed distinguishing individual growth. Vickers micro-hardness was determined obtaining values for Ni and Al3Ni2of about 100 and 800 HV/ 0.025, respectively.

Growth Kinetics of the Selected Intermetallic Phases in Ni/Al/Ni System with Various Nickel Substrate Microstructure

“…Additionally, the system is studied in many configurations with respect to the chemical composition of initial substrates (end members) and various their combinations [3,5,7,8,9,10,11]. Moreover, different experimental procedures have been employed in these studies such as: Ni/Al diffusion couples [3,5,8,9,10,12], Ni/Al/Ni sandwiches [7,13,14,15], or more complex assemblies such as multilayers, nanocoatings or aluminized nickel alloys [16,17,18,19,20,21].…”

“…Two opposite approaches are possible. First one involves situation, when as a primary phase Al 3 Ni phase precipitates and then Al 3 Ni 2 one is created [ 13 , 14 , 26 ]. Some modeling results and in-situ experiments indicated on formation of Al 3 Ni 2 phase as the first one and then Al 3 Ni [ 27 , 28 , 29 ].…”

“…As the process proceeds, the intermetallic compounds such as: AlNi, Al 3 Ni 5 and AlNi 3 are formed [ 13 ]. In the cited works the chemical composition was verified mainly by EDS technique in SEM [ 13 , 14 , 26 , 27 , 28 , 29 ]. Additionally, in [ 26 , 29 ] works, the XRD measurements were also conducted to confirm the phases’ composition present in the interconnection zones, while in [ 27 , 28 ] for the phase sequence occurrence the mathematical model was proposed.…”

Influence of Nanoscaled Surface Modification on the Reaction of Al/Ni Multilayers

“…The Al 1.1 Ni 0.9 phase contains 42-47 at % Ni [20]. Diffusion studies on Al-Ni-interfaces have shown that the formation of intermetallic phases starts with Al-rich ones [21] as a consequence of the lower melting point of the material. The sputtered parent RML contains stoichiometric composition of Al and Ni.…”

Solid-Liquid Interdiffusion (SLID) Bonding of p-Type Skutterudite Thermoelectric Material Using Al-Ni Interlayers

“…In addition, the temperature dependence of reaction rate k can be expressed by the following Arrhenius relationship:k=k0exp(−QRT) where k0 is the frequency factor, R is the Boltzmann constant, and Q is the activation energy for the growth of the designed Al 3 Ni 2 phase. According to Tumminello, et al [44], the two empirical parameters attributed to Al 3 Ni 2 phase growth, k and n are 8.5 × 10 − 8 m/s and 0.844, respectively. Based on Equations (4) and (5), complete transition to the Al 3 Ni 2 phase can be achieved within 4.6 min, which was used in the experiment.…”