Microstructure of shear-induced thixoformed Al- 4.5Cu-1.5Mg alloy via RAP and SSTT processes

• Main Authors: Siamak Nikzad, Hossein Ashuri, Mahdi Shafizadeh
• Format: Article
• Language: English
• Published: Foundry Journal Agency 2017-07-01
• Series: China Foundry
• Subjects: thixoforming; RAP; SSTT; aluminium alloys
• Online Access: http://ff.foundryworld.com/uploadfile/2017080837309197.pdf

In this research, the effect of the thixoforming temperature on the microstructure and mechanical properties was investigated in the thixoforming of the feedstock produced by the RAP (recrystallization and partial melting) and SSTT (semi-solid thermal transformation) processes for Al-4.5Cu-1.5Mg alloy. In the RAP process, the percentage reduction in area was approximately 35%. Thixoforming was done at 610, 620, and 630 °C. Globular microstructure was observed at all temperatures and conditions. The minimum average globule size was 39 μm, and it was obtained in the thixoforming of the feedstock produced by the RAP process in the section of 4 mm in diameter at 620 ° C after applying shear. Its corresponding compressive strength was -877.44 MPa. The maximum average globule size was 136 μm, and it was obtained in the thixoforming of the feedstock produced by the SSTT process in the section of 10 mm in diameter at 630 °C before applying shear. Its corresponding compressive strength was -769.18 MPa. The finest and most spherical globules, as well as the highest compressive strength were obtained at 620 °C in both RAP and SSTT states.