Intermetallics Formation, Hardness and Toughness of A413.1 Type Alloys: Role of Melt and Aging Treatments

The present study was performed on a 6061-type alloy to examine the effects of minor additions (Si, Mn, Be, Sr) of the type of precipitated Fe-based intermetallics, in terms of Fe/Si ratios. All alloys were grain refined (0.15%Ti in the form of Al-5%Ti-1%B) to minimize hot tearing during casting. The effect of these intermetallics on the alloy tensile properties was also investigated. Tensile test bars were solutionized at 520 °C followed by quenching in warm water at 60 °C to avoid cracking. The quenched bars were aged at 175 °C for periods up to 100 h. Characterization of the formed intermetallics as well as phase precipitation were carried out using field emission scanning electron microscopy. In Be-treated alloys, α-Al8Fe2SiBe phase may precipitate along with α-Al15(Fe, Mn)3Si2 phase. In addition, Be results in fragmentation of the α-Fe phase when the alloy was Sr-modified, leading to better tensile properties, compared to those obtained from the base alloy under same conditions. It should be noted that this study does not promote the use of Be as it is a toxic element.

/pdf/effect-of-si-mn-be-and-sr-addition-on-the-tensile-properties-13dg6lf1.pdf

Effect of Si, Mn, Be and Sr Addition on the Tensile Properties of 6061 Type Alloys: Role of Aging Treatment

The requirements of lightweighting structures drive the improvement of mechanical properties of cast Al–Si–Mg alloys Grain refinement is a way to improve mechanical properties Al5Ti1B master alloy with TiB2 and extra Ti is widely accepted in industry for the grain refinement of aluminium alloys, especially wrought aluminium alloys, but it is hard to meet the expectations of cast Al–Si–Mg alloys due to the poisoning effect by Si Al3Ti3B master alloy with TiB2 and extra B was prepared for the grain refinement of cast Al–Si–Mg alloys The microstructure of cast Al9Si045Mg alloys under the refinement of Al3Ti3B and Al5Ti1B master alloys were investigated The grain size of the primary α-Al phase in the Al9Si045Mg alloy refined by Al5Ti1B is 511 ± 104 μm, and that is decreased significantly by 55% to 231 ± 64 μm in the Al3Ti3B refined alloy The mechanisms of grain refinement were discussed

/pdf/grain-refinement-of-al-si-mg-cast-alloys-by-al3ti3b-master-2cmesdcfpr.pdf

Xixi Dong

Papers

Grain refinement of Al–Si–Mg cast alloys by Al3Ti3B master alloy