Effect of Ultrasonic Treatment on Grain Structure, Eutectic Phase and Mechanical Properties of an Al–6.2 wt% Cu Alloy
- 8 Downloads
The microstructural modification of eutectic phase is a crucial factor for the mechanical properties strengthening of the Al–Cu binary alloy. In this paper, Al–6.2% Cu melts were subjected to ultrasonic treatment from 710 or 660 °C with different durations. The microstructural evolutions of primary α-Al grains and α-Al + θ-Al2Cu eutectic phase under ultrasonication were investigated based on the nucleation and growth behavior. Results indicated that with the increase of ultrasonic processing time, the growth of dendritic or petaloid grains were completely suppressed and noticeable refinement to globular morphology were observed for α-Al grains. Meanwhile, broad lamella-like eutectic structure transformed to debris or even particles with continuous ultrasonication. Accordingly, the area fraction, average length and width of coarsening eutectic lamellas were dramatically reduced. In addition, the decrease of coarsening eutectic phase rather than the refinement of α-Al grains was found to be the main contributor to the enhancement of mechanical properties for Al–6.2% Cu alloy. The mechanisms underlying the transformation of eutectic phase under ultrasonic treatment was also interpreted based on the experimental results.
KeywordsUltrasonic treatment α-Al phase α-Al + θ-Al2Cu eutectic phase Mechanical properties
This work has received financial support from the National Natural Science Foundation of China (Grant Nos. U1637601, 51575539, 51805549), the Key Projects of Hunan Province Science and Technology Plan (No. 2016GK1004). In addition, special thanks to Dr. Zhilin Liu for paper revision.
- 31.G.F. Balandin, Fundamentals of the Theory of Formation of Castings (In Two Parts) [in Russian], Part 1 (Mashinostroenie, Moscow, 1976)Google Scholar
- 34.D.G. Eskin, Physical Metallurgy of Direct Chill Casting of Aluminum Alloys, 1st edn. (CRC Press, Boca Raton, 2018)Google Scholar
- 39.D.G. Eskin, I. Tzanakis, In Solidification Processing of Metallic Alloys Under External Fields, ed. by D.G. Eskin, J.W. Mi (Springer, Switzerland, 2018) p. 153Google Scholar