Thermo-Calc Prediction of Mushy Zone in AlSiFeMn Alloys

Abstract

Convection forces can cause significant segregation within the liquid during directional solidification, influencing the structure of the mushy zone and the type and distribution of phases present in the solidified alloy. The solidification behavior of AlSiFeMn alloys with strong convection was investigated via experimental results combined with thermodynamic calculations. Experimental specimens were processed in a directional solidification facility with forced melt flow, resulting in high levels of elemental segregation across samples. The resulting local compositions were located on phase diagrams Al-Si-Fe, Al-Si-Mn and Al-Fe-Mn for prediction of the variation in solidification behavior. Phase mass fraction diagrams created in Thermo-Calc showed the effect of segregation on the characteristic temperatures, mushy zone length and the order of occurring phases precipitating across specimens. These findings were used to create 2D maps for visualization of the mushy zone, mass fraction of α-Al dendrites, β-Al 5 FeSi, Al 15 Si 2 Mn 4 and their spatial location. The specimen centers showed enrichment in AlSi-eutectic but for β-Al 5 FeSi and Al 15 Si 2 Mn 4 results are ambiguous. Fe-phases start to grow mainly behind the dendrites tips and in general may flow between them. Mn-rich phases start to precipitate at higher temperatures than β and in many places before α-Al and in this way may flow in the melt above the mushy zone.

Prediction of phase composition and mechanical properties Fe–Cr–C–B–Ti–Cu hardfacing alloys: Modeling and experimental Validations

“…The following equations were used to determine the shown mechanical properties Eq. (12) , (13) , (14) , (15) , (16) ) [ 122 , 124 , 158 ]: …”

“…Indentation results corrected according to procedure reported in Ref. [ 122 ] are presented in Table 12 and the SEM images of the indents are shown in Fig. 11 .…”

“…Besides, the introduction of an exothermic addition increases the deposition rate [ 49 ], improves the morphology of the weld bead [ 51 , 119 ], arc process efficiency [ 119 ] and the hardfacing process stability [ 120 ]. Тrembach et al [ 49 ] determined that the introduction of exothermic addition (CuO–Al) of to the core filler had a significant effect on such indicators of the weld bead morphology, microstructure and mechanical properties [ 87 , [121] , [122] , [123] ].…”

Morphology and Distribution of α-Al and Mn-rich Phases in Al-Si-Mn Alloys under an Electromagnetic Stirring

“…These phases in aluminum alloys are known to author from earlier studies, projects and papers (e.g. in [1][2][3][14][15][16][17][18][19]). The composition of the proposed alloys was first determined based on available in the literature phase diagrams, but the exact composition and resulting precipitation sequence needed detailed calculations, in order to achieve the proposed, e.g.…”