Effect of Vanadium Micro-alloying on the Microstructure and Mechanical Properties of Stir Cast Al 354.0 Alloy

• Published in: Metallography, microstructure, and analysis Vol. 12; no. 5; pp. 849 - 862
• Main Authors: Mahton, Yogendra, Pandiripalli, Mahesh, Saha, Partha
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.10.2023; Springer Nature B.V
• Subjects: Aging (artificial); Alloys; Aluminum base alloys; Ambient temperature; Characterization and Evaluation of Materials; Chemistry and Materials Science; Compressive properties; Elongation; Emission analysis; Field emission microscopy; Grain boundaries; Grain growth; Ingot casting; Intermetallic compounds; Intermetallic phases; Magnesium compounds; Materials Science; Mechanical properties; Metal silicides; Metallic Materials; Microalloying; Microscopy; Microstructure; Morphology; Nanotechnology; Optical microscopy; Original Research Article; Precipitates; Silicon; Solution heat treatment; Squeeze casting; Strengthening; Structural Materials; Surfaces and Interfaces; Thin Films; Vanadium; Yield strength; Mechanical properties; Heat treatment; Microstructure; Al 354.0 alloy; Wear; Vanadium
• ISSN: 2192-9262; 2192-9270
• DOI: 10.1007/s13632-023-01010-9

The present work investigates the effect of vanadium (V) micro-alloying addition on the microstructural evolution and mechanical properties of Al 354.0 alloy in as-cast and T6 condition. In particular, Al 354.0 with and without 0.3 wt.% V was developed by squeeze casting technique. The as-cast ingots were subjected to two types of heat treatment schedules, i.e., solution heat treatment at 495 °C for 8 h, followed by rapid water quenching and artificial aging at 190 °C for 2 h (T6), and solution heat treatment at 515 °C for 10 h, followed by rapid water quenching and artificial aging at 210 °C for 6 h (MT6), to modify the microstructure, morphology, and distribution of Al-, Cu-, and Mg-containing secondary phase(s). The phase and microstructure of unmodified and 0.3 wt.% V-modified alloys were analyzed using x-ray diffraction, optical microscopy, and field emission scanning electron microscopy coupled with energy-dispersive x-ray spectroscopy. Detailed analyses show that Al 2 Cu/Al 2 Cu(SiMg), Al 5 Si 2 Mg, and Al 2 Si were the strengthening phases in the unmodified alloy, whereas 0.3 wt.% V-modified alloy contains Al 10 V/Al 10 V(Mg), Al 3 Cu, Mg 2 Si, Al 4 Si, and Al(SiCuMg) as the primary strengthening phase(s). A subtle increase in the mechanical properties was evident in the 0.3 wt.% V-modified alloy compared to unmodified alloy at ambient temperature due to the presence of Al 10 V/Al 10 V(Mg) fine precipitates and Al(SiCuMg) intermetallic along the grain boundaries (GBs) preventing dislocation movement. T6 treatment resulted in a grain growth where needle/plate morphology of eutectic silicon was partially converted into spheroidal morphology, and Al 2 Cu/AlSiCuMg, Mg 2 Si, and Al 10 V/Al 10 V(Mg) intermetallic phases emerged increasing the tensile (0.3% V modified vs. unmodified; YS: ~ 287 vs. ~ 268 MPa, UTS: ~ 330 vs. ~ 334 MPa, elongation: ~ 1.5% vs. ~ 2.6%), compression (0.3% V modified vs. unmodified YS: ~ 497 vs. ~ 460 MPa, UCS: ~ 790 vs. ~ 776 MPa, compressive strain: ~ 40% vs. ~ 42%), and wear properties. However, modified T6 treatment (MT6) resulted in a grain growth where needle/plate morphology of eutectic silicon converted into spheroidal morphology, and Al 2 Cu partially and Mg 2 Si precipitates along the GBs were completely dissolved in the α -Al matrix by incipient melting improving the ductility (~5.9%) at the expense of yield strength (~104 MPa) and ultimate tensile strength (~218 MPa).