3D characterization of ultrasonic melt processing on the microstructural refinement of AlCu alloys using synchrotron X-ray tomography

• Published in: Materials characterization Vol. 153; pp. 354 - 365
• Main Authors: Zhao, Yuliang, Song, Dongfu, Lin, Bo, Zhang, Chun, Zheng, Donghai, Inguva, Saikumar, Li, Tao, Sun, Zhenzhong, Wang, Zhi, Zhang, Weiwen
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.07.2019
• Subjects: Aluminum alloys; Fe-rich phases; Pores; Refinement; Synchrotron X-ray tomography; Ultrasonic melting processing; Ultrasonic melting processing; Refinement; Fe-rich phases; Aluminum alloys; Pores; Synchrotron X-ray tomography
• ISSN: 1044-5803; 1873-4189
• DOI: 10.1016/j.matchar.2019.04.040

The effect of ultrasonic melt processing (USP) on the three-dimensional (3D) architecture of intermetallic phases and pores in two multicomponent cast Al–5.0Cu–0.6Mn–0.5(1.0) Fe alloys is characterized using conventional microscopy and synchrotron X-ray microtomography. The two alloys are found to contain intermetallic phases, such as α-Al15(FeMn)3Cu2, β-Al7Cu2Fe, Al3(FeMn), Al6(FeMn), and Al2Cu, that have complex networked morphology in 3D. The refined and equiaxed microstructures can be obtained by the application of USP. The results show that USP effectively reduce the volume fraction, interconnectivity, and equivalent diameter of the intermetallic phases in both alloys. The grain sizes of 0.5Fe and 1.0Fe alloys are decreased from 16.9 μm and 15.8 μm without USP to 13.3 μm and 12.2 μm with USP, respectively. USP can effectively reduce the volume fraction of pores in both alloys due to the ultrasonic degassing effect. The main refinement mechanisms are fragmentation of primary and secondary dendrites induced by acoustic bubbles and acoustic streaming flow. •3D morphology of intermetallic phases was characterized by synchrotron X-ray tomography.•Ultrasonic melt processing led to a homogenous, refined and equiaxed microstructure.•Ultrasound reduces the interconnectivity, volume and diameter of intermetallic phases.