Analysis of the Cutting Temperatures along the Macrostructure of a Directionally Solidified Al-7wt%Si Alloy

Abstract

The aim of this research is to investigate the influence of solidification thermal parameters on the macrostructure of an Al-7wt%Si alloy during the horizontal directional solidification under unsteady-state heat flow conditions and its correlation with cutting temperatures. The solidification experiments were instrumented by thermocouples and an experimental approach was developed to quantitatively determine the solidification thermal parameters considered. The observation of the macrostructures has indicated that the columnar-to-equiaxed transition occurred in a sharp plane parallel to the chill wall and a higher average cutting temperature was obtained for the columnar structure.

Interconnection between the solidification and precipitation hardening processes of an AlSiCu alloy

“…(V L ) −2/3 and λ 2 = Constant. (T R ) −1/3 , respectively, whose exponents −2/3 and −1/3 are concordant with the literature for Al-based alloys [1,2,[10][11][12][16][17][18]27,28,[40][41][42][43]47,50,51]. Figure 6 also shows a comparative analysis between the results of this work and those reported by Costa et al [1], and an excellent agreement has been observed for the two assumed solution, despite a slight disagreement of the trend of λ 2 = f (P) found for the time equal to 8 h.…”

“…As mentioned, in this work the measured average Ø values are between the ranges of 0.71–1 of circularity of Si particles, since in this range these particles have been considered like perfect circles. Silva et al [41,42] have reported that spherical-like Si particles improve manufacturing properties such as machinability and weldability. The results of this work for both as-cast and heat treated samples are shown in Figure 12.…”

“…Iron is the most common impurity found in aluminium alloys. The solubility of Fe in liquid aluminium is quite high; on the other hand, at 660°C it is very low ( ≈ 0.05 wt-%) and at room temperature even lower [1,[42][43][44][45][46]. It is known that the Fe combines with other alloying elements such as Al, Si, Cu and Mg to form a number of brittle phases, which influence the as-cast microstructure.…”

“…In the as-cast microstructures of Al–Si–Cu alloys, the Al 2 Cu phase may be present in different forms, such as blocks, eutectic or as a mixture of both types [3,32–36]. It is known that finer microstructures, by imposing high growth and cooling rates during solidification, allow a complete solubility of Al 2 Cu with lower times and temperatures [1,3–9,11,12,15,29–31,38–42]. Samuel et al [3], Li et al [35], Djurdjevic et al [32] and Han et al [36] studied the dissolution of the Al 2 Cu intermetallic compound during the solution treatment in Al–Si–Cu alloys, and Han et al [36] have observed that the eutectic type is fragmented in smaller spheroidal segments and the block dissolves by radial diffusion of Cu in the surrounding matrix.…”

Influence of Solidification Parameters and Solute Content on the Machinability of Two Lead-Free Babbit Metals

“…Ductility, hardness, and thermal properties have a significant effect on the acting forces and the generated temperature. Thus, there is great importance in measuring temperatures during machining operations and in studying their effects, as one of the machinability criteria [18][19][20][21].…”