Tailoring microstructure, tensile properties and fracture process via transient directional solidification of Zn-Sn alloys

Abstract

The aim of the present study is to determine interrelations of microstructure length-scale, tensile properties and fracture mechanisms of hypoeutectic Zn-Sn alloys. Three compositions were subjected to transient directional solidification: Zn-10, 20 and 40 wt%Sn. Grainy-faceted cleavage has been observed as the predominant mode of fracture, which propagated across the Zn-rich plate cells. A clear influence of the formed microstructure and proportion of eutectic may be noted in the fracture features, with alveolar structures also appearing in fracture surfaces. Growth laws relating the eutectic spacing with the growth rate are proposed, which are able to encompass both steady-state and transient solidification conditions. Hall-Petch type equations are developed relating the yield and ultimate tensile strengths, σ y and σ u , respectively, to the cellular spacing, λ, in which smaller λ values resulted in higher σ y and σ u.

Recent research and progress of biodegradable zinc alloys and composites for biomedical applications: Biomechanical and biocorrosion perspectives

“…This technique is an alternative to traditional casting, where a special water-cooled apparatus is utilized to assist directional solidification (DS) and the process is carried out by controlling several conditions of heat flow. Moreover, a theoretical/experimental or combined approach is employed to calculate various solidification parameters (such as tip growth rate, cooling rate) that affect the microstructure of the resultant Zn alloys [ 112 , 113 ]. Zn–Mg alloys fabricated by TDS and their microstructures and mechanical properties are summarized in Table 3 .…”

Microstructure Growth Morphologies, Macrosegregation, and Microhardness in Bi–Sb Thermal Interface Alloys

“…After allowing time for the melt to become homogeneous, the molten alloys were poured into a directional solidification setup ( Figure 2), which was designed in such a way that heat was extracted only through the water-cooled bottom, made of low carbon steel, leading the directionally solidified (DS) casting to grow vertically upward, as further described in previous studies. [37,38] Continuous temperature measurements during solidification were acquired via the output of a bank of fine type-J thermocouples kept at different positions along the length of the castings. When the thermocouple closest to the chilled base measured a temperature of 10% above the alloy liquidus temperature, the electrical windings were disconnected, and the water flow was immediately initiated, thus permitting the onset of the directional solidification.…”

“…Weighed quantities of such metals were placed in a graphite crucible, which were inserted in a melting furnace at 600 °C, where the metals were completely melted, considering the liquidus temperatures ( T L ) of each examined alloy from the phase diagrams calculated by the Thermo‐Calc software, as shown in Figure . After allowing time for the melt to become homogeneous, the molten alloys were poured into a directional solidification setup (Figure ), which was designed in such a way that heat was extracted only through the water‐cooled bottom, made of low carbon steel, leading the directionally solidified (DS) casting to grow vertically upward, as further described in previous studies …”

Microstructure evolution of as-extruded Zn–0.62Mn alloys during room temperature compression

“…The common alloying elements are Mg, Cu, Fe, Ca, Fe, Sr, Sn, Bi, Mn, Ag, Al, Ge, Li, Ti and Zr. The second phase has a great affection on the microstructure and mechanical properties of Zn alloys [7][8][9][10][11][12][13][14][15][16][17][18][19]. Among the above elements, Mn has attracted much attention because it is easy to improve the elongation of Zn alloys [20].…”