Ultrasonic-Assisted Soldering of 5056 Aluminum Alloy Using Quasi-Melting Zn-Sn Alloy

Abstract

TORU NAGAOKA, YOSHIAKI MORISADA, MASAO FUKUSUMI, and TADASHI TAKEMOTO To obtain sound butt-joints of 5056 aluminum alloy rods, ultrasonic-assisted soldering was conducted using Zn-18Sn and Zn-60Sn alloys. Each solder foil was inserted between rods of 5056 aluminum alloy. Ultrasonic vibration was propagated to faying surfaces at soldering temperatures below the liquidus temperature of the solder alloys, and then the samples were air cooled to room temperature. The optimum vibration time at the soldering temperature must be more than 2 seconds to have complete wetting and less than 4 seconds to avoid excessive dissolution of the 5056 alloy. The 5056 alloy joints soldered using quasi-melting. Zn-Sn alloys showed greater strength than the joints soldered at the temperatures over its respective liquidus temperature. As the soldering temperature was increased, the increased formation of the intermetallic compound Mg 2 Sn or phases containing Mg generated by dissolution of 5056 into the solder layer decreased the joint strength. Ultrasonic-assisted soldering at an optimum temperature between solidus and liquidus of the Zn-Sn alloys is an important consideration for producing sound joints with sufficient strength.

Wetting of Al pads by Sn–8.8Zn and Sn–8.7Zn–1.5(Ag, In) alloys

“…Unfortunately, these temperatures are rather high considering the melting temperature of aluminum (660°C), also brittle Si-rich precipitates tend to form in such joints. More recently, ultrasonicassisted soldering was proposed [4], yet this technique cannot easily be applied to the commonly used soldering equipment. Alternatively, the soldering of aluminum can be achieved using solders based on Sn or Zn [5] and a specific flux with the Sn-based solders being the preferred choice due to their lower melting temperature.…”

Bonding mechanism of lead-free solder and glass plate by ultrasonic assisted soldering method

“…Thus, ultrasonication contributes to an enhancement of the wettability of solder to the glass and accelerates solder-glass bonding. According to the ultrasonically brazing of Al alloy joints [23,26], the enhancement of the wettability by ultrasonication is attributed to the disruption of the surface oxide film. However, the enhancement of the wettability observed in this study is caused by other mechanisms because the main composition of the glass slide is silicon oxide.…”

“…The two materials can then be bonded via the IMC layer. Application of the ultrasonic assisted soldering method to the joining of aluminum alloys has been examined and good strength has been obtained [24][25][26].…”

Selection of soldering temperature for ultrasonic-assisted soldering of 5056 aluminum alloy using Zn–Al system solders

“…Ultrasonic-assisted soldering conditions were optimized in previous studies (Nagaoka et al, 2009(Nagaoka et al, , 2010. A constant pressure of 0.5 MPa was applied during the ultrasonic-assisted soldering process.…”

“…However, significant dissolution of 5056 aluminum substrates might be derived because eutectic reaction between Zn filler and Al substrates occurred during the joining process. In our previous works (Nagaoka et al, 2010), ultrasonic-assisted soldering using quasi-melting Zn-Sn solder alloy succeeded to suppress the dissolution of 5056-Al substrate during the soldering process. Though high-strength joints were obtained, using solders containing Sn deteriorated the corrosion resistance of aluminum solder joints.…”