Bridgman Type Directional Solidification Apparatus Research Articles

Experimental determination of interfacial energy for solid Al in the Al-Sn-Mg eutectic system with Bridgman-type apparatus

The equilibrated grain boundary groove shape of solid Al in equilibrium with Al-Sn-Mg eutectic liquid was observed by using a Bridgman type directional solidification apparatus. The ratio of the thermal conductivity of the equilibrated liquid to the thermal conductivity of solid Al has been obtained as 0.91. In addition, the average Gibbs-Thomson coefficient, Γ‾=(4.20±0.35)×10−8Km, the solid-liquid interfacial energy, σSL=180.68±23.48mJ/m2 and the grain boundary energy, σGB=309.30±29.47mJ/m2, in the Al/Al-Sn-Mg system have been calculated from the measured grain boundary shapes.

Determination of solid–liquid interfacial energy of Ni3Sn2 phase by grain boundary groove method in a temperature gradient

The Ni3Sn2 phase plays an important role in numerous fields including solder alloys and lithium storage. However, the precise measurements of many parameters which are essential in describing the physical properties of this phase, such the Gibbs-Thomson coefficient, solid–liquid interfacial energy, grain boundary energy and entropy of fusion per unit volume have not been carried out yet. In this work, the equilibrated grain boundary groove (GBG) shapes for a solid Ni3Sn2 phase in equilibrium with the liquid were observed from Sn-36 at.%Ni peritectic alloy in a linear temperature gradient by using a Bridgman type directional solidification apparatus after experiencing a thermal stabilization time of 8 h. The time required to obtain the GBG shapes in this alloy with a large freezing range was analyzed through the temperature gradient zone melting (TGZM) theory. The Gibbs-Thomson coefficient, solid-liquid interfacial energy and grain boundary energy for the solid Ni3Sn2 phase in equilibrium with liquid were determined in this work, which will help the growth and property control of the fields mentioned above.

Effects of Growth Rates and Compositions on Dendrite Arm Spacings in Directionally Solidified Al-Zn Alloys

Dendritic spacing can affect microsegregation profiles and also the formation of secondary phases within interdendritic regions, which influences the mechanical properties of cast structures. To understand dendritic spacings, it is important to understand the effects of growth rate and composition on primary dendrite arm spacing (λ 1) and secondary dendrite arm spacing (λ 2). In this study, aluminum alloys with concentrations of (1, 3, and 5 wt pct) Zn were directionally solidified upwards using a Bridgman-type directional solidification apparatus under a constant temperature gradient (10.3 K/mm), resulting in a wide range of growth rates (8.3–165.0 μm/s). Microstructural parameters, λ 1 and λ 2 were measured and expressed as functions of growth rate and composition using a linear regression analysis method. The values of λ 1 and λ 2 decreased with increasing growth rates. However, the values of λ 1 increased with increasing concentration of Zn in the Al-Zn alloy, but the values of λ 2 decreased systematically with an increased Zn concentration. In addition, a transition from a cellular to a dendritic structure was observed at a relatively low growth rate (16.5 μm/s) in this study of binary alloys. The experimental results were compared with predictive theoretical models as well as experimental works for dendritic spacing.

Microstructural Evolution and Mechanical Properties in Directionally Solidified Sn–10.2 Sb Peritectic Alloy at a Constant Temperature Gradient

The Sn–10.2 Sb (mass fraction) peritectic alloy was prepared using a vacuum melting furnace and a hot filling furnace. The samples were directionally solidified upwards at steady state conditions with a constant temperature gradient (G=4.5±0.2 K. mm-1) under different growth velocities (V=13.3–266.7 µm. s-1) in a Bridgman-type directional solidification apparatus. The effects of the growth velocity (V) on the dendritic spacings were investigated. Primary dendrite arm spacing (PDAS) of α phase in directionally solidified Sn–10.2 Sb peritectic alloy was measured on the longitudinal and transverse sections of 4 mm diameter cylindrical samples. Secondary dendrite arm spacing (SDAS) was measured on the longitudinal section. The experimental results show that the measured PDAS (λ1L, λ1T) and SDAS (λ2) decrease with increasing growth velocity. The dependence of PDAS, SDAS, microhardness (HV) and compressive strength (σc) on the growth velocity were determined by using a linear regression analysis. The experimental results were compared with the previous experimental results and the results of the experimental models.

Thermal Conductivity of Solid Phases for Naphtol, Camphene, Salol, and Bezil

Dependencies of thermal conductivity of solid phases on temperature have been investigated by using radial heat flow apparatus for naphthol, camphene, salol, and benzil. From graphs of the solid phase’s thermal conductivity variations versus temperature, the thermal conductivities of the solid phases for naphthol, camphene, salol, and benzil have been determined at their melting temperatures. The ratios of thermal conductivity of the liquid phase to thermal conductivity of the solid phase for naphthol, camphene, salol, and benzil have also been determined with a Bridgman-type directional solidification apparatus at their melting temperatures.

Temperature Gradient Estimation of Floating Zone Furnace by Mean Lamellar Spacing Measurement in DS-processed TiAl Alloys

In this study, the temperature gradient of a floating zone (FZ) apparatus, which is very difficult to directly measure, could be estimated by using the relationships between the lamellar spacing of directionally solidified TiAl alloys and the solidification rate, It was found that the calculated temperature gradient of the FZ apparatus was much higher, and almost ten times higher than that of a Bridgman type directional solidification apparatus.

Temperature dependency of thermal conductivity of solid phases for fatty acids

Thermal conductivity variations with temperature of solid phases for lauric acid (LA), myristic acid (MA), pivalic acid (PA), and stearic acid (SA) have been measured with radial heat-flow method. Temperature dependencies of the thermal conductivity for same organic materials have been obtained by linear regression analysis. From graphs of thermal conductivity versus temperature, the thermal conductivity of solid phase at their melting temperature and temperature coefficients of thermal conductivity for LA, MA, PA, and SA have been found to be 0.37, 0.39, 0.23, and 0.35 W K−1 m−1 and 0.00935, 0.00446, 0.01095, and 0.00295 K−1, respectively. The ratios of thermal conductivity of liquid phase to thermal conductivity of solid phase for LA, MA, PA, and SA have also been measured to be 0.52, 0.48, 0.25, and 0.59, respectively, with a Bridgman-type directional solidification apparatus.

The solid–liquid interfacial energy for solid Zn solution at the eutectic Zn–Sn–Mg ternary alloy

Abstract The Gibbs–Thomson coefficient, Γ , the effective entropy change, Δ S f , the solid–liquid interfacial energy, σ SL , and the grain boundary energy, σ GB , for solid Zn solution at the eutectic Zn–Sn–Mg ternary alloy have been calculated using the grain boundary groove method with Bridgman-type directional solidification apparatus.

Thermal Conductivity of Solid and Liquid Phases for Pb-Cd Alloys

Thermal conductivities of solid phases for pure Pb and Pb-x weight% Cd (5, 12, 17.4, 50, and 95) binary alloys were measured with a radial heat flow apparatus. Thermal conductivity depending on temperature and composition for pure Pb and Pb-x weight% Cd (5, 12, 17.4, 50, and 95) binary alloys were obtained to be , , , , , and . The thermal conductivity ratio of liquid phase to solid phase for the eutectic Pb-17.4 weight% Cd alloy at its melting temperature is found to be 1.31 with a Bridgman-type directional solidification apparatus. Thus, the thermal conductivity of the liquid phase for the eutectic alloy at its melting temperature was found to be by using the values of solid phase thermal conductivity and the thermal conductivity ratio of liquid phase to solid phase.

Relationship between Growth Rates and Dendritic Microstructure Parameters in Al-5wt. Zn Binary Alloy

Al-5 wt.% Zn samples were prepared using high purity (99.99%) metals in graphite crucibles. The samples were directionally solidified upward with a constant temperature gradient (G= 5.5 Kmm-1) and different growth rates,V, (8.25-165 μm/s) in a Bridgman type directional solidification apparatus. The dendritic spacings (λ1: Primary dendrite arm spacing, and λ2: Secondary dendrite arm spacing) were measured from the longitudinal sections of the samples and λ1was also measured from the transverse sections. The measured spacings were expressed as functions of the growth rates by using a linear regression analysis. The effect ofVon λ1and λ2were investigated. The experimental results were compared with the results of the current theoretical and numerical models and similar previous experimental results.

Measurements of Thermal Conductivity Variations with Temperature for the Organic Analog of the Nonmetal–Nonmetal System: Urea–4-Bromo-2-Nitroaniline

Thermal conductivity variations with temperature for solid phases in the Urea (U)–[X] mol pct 4-bromo-2-nitroaniline (BNA) system (X = 0, 2, 45, 89.9, and 100) were measured using the radial heat flow method. From graphs of thermal conductivity variations with temperature, the thermal conductivities of the solid phases at their melting temperature and temperature coefficients for the U–[X] mol pct BNA system (X = 0, 2, 45, 89.9, and 100) were found to be 0.26, 0.55, 0.46, 0.38, and 0.23 W/Km and 0.007781, 0.005552, 0.002058, 0.002188, and 0.002811 K−1, respectively. The ratios of thermal conductivity of the liquid phase to thermal conductivity of the solid phase in the U–[X] mol pct BNA system (X = 0, 2, 45, 89.9, and 100) were also measured to be 0.30, 0.44, 0.46, 0.49, and 0.51, respectively, with a Bridgman-type directional solidification apparatus at their melting temperature.

Determination of thermal conductivities of Sn–Zn lead-free solder alloys with radial heat flow and Bridgman-type apparatus

The variations of thermal conductivities of solid phases versus temperature for pure Sn, pure Zn and Sn–9 wt.% Zn, Sn–14 wt.% Zn, Sn–50 wt.% Zn, Sn–80 wt.% Zn binary alloys were measured with a radial heat flow apparatus. The thermal conductivity ratios of liquid phase to solid phase for the pure Sn, pure Zn and eutectic Sn–9 wt.% Zn alloy at their melting temperature are found with a Bridgman-type directional solidification apparatus. Thus, the thermal conductivities of liquid phases for pure Sn, pure Zn and eutectic Sn–9 wt.% Zn binary alloy at their melting temperature were evaluated by using the values of solid phase thermal conductivities and the thermal conductivity ratios of liquid phase to solid phase.

Determination of thermal conductivities of solid and liquid phases for rich-Sn compositions of Sn-Mg alloy

The variations of thermal conductivities of solid phases versus temperature for pure Sn and Sn-1 wt% Mg, Sn-2 wt% Mg, and Sn-6 wt% Mg binary alloys were measured with a radial heat flow apparatus. Thermal conductivity variations versus temperature for pure Sn and Sn-1 wt% Mg, Sn-2 wt% Mg, and Sn-6 wt% Mg binary alloys were found to be 60.60 ± 3.63, 61.99 ± 3.71, 68.29 ± 4.09, and 82.04 ± 4.92 W/Km, respectively. The thermal conductivity ratios of liquid phase to solid phase for pure Sn and eutectic Sn-2 wt% Mg alloy at their melting temperature were found to be 1.11 and 1.08, respectively, with a Bridgman type directional solidification apparatus. Thus the thermal conductivities of liquid phases for pure Sn and eutectic Sn-2 wt% Mg binary alloy at their melting temperature were evaluated to be 67.26 ± 4.03 and 73.75 ± 4.42 W/Km, respectively, by using the values of solid phase thermal conductivities and the thermal conductivity ratios of the liquid phase to the solid phase.

Dependency of thermal conductivity on the temperature and composition of d-camphor in the neopentylglycol–d-camphor alloys

Dependencies of thermal conductivity of solid phases for neopentylglycol (NPG)–[x]wt.% d-camphor (DC), x=0, 3, 30, 46, 70 and 96 alloys on temperature and composition have been investigated by using radial heat flow apparatus. From graphs of the solid phases thermal conductivity variations versus temperature, the thermal conductivities of the solid phases at their melting temperature and temperature coefficients for NPG–[x] wt.% DC, x=0, 3, 30, 46, 70 and 96 alloys were found to be 0.29, 0.28, 0.27, 0.26, 0.25 and 0.24W/Km and 0.002996, 0.002694, 0.005690, 0.010626, 0.003520 and 0.001404K−1, respectively. The ratios of thermal conductivity of liquid phase to thermal conductivity of solid phase for NPG–[x]wt.% DC, x=0, 3, 30, 46, 70 and 96 alloys at their melting temperature were found with a Bridgman type directional solidification apparatus to be 1.07, 0.93, 0.43, 0.50, 0.40 and 0.35, respectively.

Variations of microhardness with solidification parameters and electrical resistivity with temperature for Al–Cu–Ag eutectic alloy

Al–Cu–Ag eutectic alloy was directionally solidified upwards with different growth rates (1.83–498.25 μm/s) at a constant temperature gradient (8.79 K/mm) and with different temperature gradients (3.99–8.79 K/mm) at a constant growth rate (8.30 μm/s) by using a Bridgman type directional solidification apparatus. The dependence of microhardness (HV) on the growth rate (V), temperature gradient (G) and microstructure parameter (λ) were found to be HV = k 1 V 0.10, HV = k 2 G 0.13 and HV = k 3 λ −0.22, respectively. The electrical resistivity of the Al–Cu–Ag eutectic cast alloy increases linearly with the temperature in the range of 300–780 K. The enthalpy of fusion and specific heat change during melting for same alloy were also determined to be 223.8 J/g, and 0.433 J/g K, respectively by a differential scanning calorimeter from heating curve during the transformation from eutectic solid to eutectic liquid.

The effect of composition on microhardness and determination of electrical and thermal properties in the Sn-Cu alloys

Tin-copper of (99.99%) high purity alloys were directionally solidified upward with different compositions, C o , Sn-(1.2, 3, 6 and 15)wt% Cu under two different solidification conditions (temperature gradient (G) = 8 K/mm, growth rate (V) = 7 μm/s and G = 4 K/mm, V = 130 μm/s) using a Bridgman type directional solidification apparatus. The measurements of microhardness of directionally solidified samples were obtained by using a microhardness test device. The dependence of microhardness HV (Vickers Hardness) on composition was analyzed. According to these results, it has been found that the values of HV increase with the increasing Cu content (C o ). Variation of electrical resistivity (ρ) and electrical conductivity (σ) with the temperature were also measured by using a standard d.c. four-point probe technique. The enthalpy of fusion (∆H) and specific heat (Cp) of the Sn-Cu alloys were determined from heating curve during the transformation from solid to liquid phase by using differential scanning calorimeter (DSC).

Determination of solid–liquid interfacial energy for a solid Sn in equilibrium with a Sn–Ag–Zn eutectic liquid

The equilibrated grain boundary groove shapes for a solid Sn in equilibrium with a Sn–Ag–Zn eutectic liquid were observed in a linear temperature gradient by using a Bridgman type directional solidification apparatus. The Gibbs–Thomson coefficient, solid–liquid interfacial energy and grain boundary energy for a solid Sn in equilibrium with a Sn–Ag–Zn eutectic liquid were determined to be (8.21 ± 0.7) × 10 −8 Km, (116.2 ± 15.1) × 10 −3 J m −2 and (228.1 ± 34.2) × 10 −3 J m −2, respectively from observed grain boundary groove shapes. A comparison of present results with the previous experimental and theoretical results for similar solids in equilibrium with the different liquid was also made.

Thermal conductivities of solid and liquid phases for pure Al, pure Sn and their binary alloys

The variations of thermal conductivities of solid phases versus temperature for pure Sn, pure Al and Sn–0.5 wt.% Al, Sn–2.2 wt.% Al, Sn–25 wt.% Al, Sn–50 wt.% Al, Sn–75 wt.% Al binary alloys were measured with a radial heat flow apparatus. From thermal conductivity variations versus temperature, the thermal conductivities of the solid phases at their melting temperature and temperature coefficients for same materials were also found to be 60.60 ± 0.06, 208.80 ± 0.22, 69.70 ± 0.07, 80.30 ± 0.08, 112.30 ± 0.12, 142.00 ± 0.15, 188.50 ± 0.20 W/K m and 0.00098, 0.00062, 0.00127, 0.00114, 0.00112, 0.00150, 0.00116 K −1, respectively. The thermal conductivity ratios of liquid phase to solid phase for the pure Sn, pure Al and eutectic Sn–0.5 wt.% Al alloy at their melting temperature are found to be 1.11, 1.13, 1.06 with a Bridgman type directional solidification apparatus, respectively. Thus the thermal conductivities of liquid phases for pure Sn, pure Al and eutectic Sn–0.5 wt.% Al binary alloy at their melting temperature were evaluated to be 67.26, 235.94 and 73.88 W/K m, respectively by using the values of solid phase thermal conductivities and the thermal conductivity ratios of liquid phase to solid phase.

Investigation of the effect of composition on microhardness and determination of thermo-physical properties in the Zn–Cu alloys

Zinc–copper of (99.99%) high purity alloys were directionally solidified upward with different compositions, C o, Zn–(0.7,1.5, 2.4 and 7.37) wt.% Cu under two different solidification conditions ( G = 3.85 K/mm, V = 0.0083 mm/s and G = 8.70 K/mm, V = 0.436 mm/s) using a Bridgman type directional solidification apparatus. The measurements of microhardness of directionally solidified samples were made by using a microhardness test device. The dependence of microhardness (HV) on composition was analyzed. According to these results, it has been found that the values of HV increase with the increasing Cu content (C o). Variation of electrical resistivity ( ρ) and electrical conductivity ( σ) with the temperature were also measured by using a standard d.c. four-point probe technique. The enthalpy of fusion (Δ H) and specific heat ( Cp) of the Zn–Cu alloys were determined from heating curve during the transformation from solid to liquid phase by using differential scanning calorimeter (DSC).

Determination of thermo-electrical properties in Sn based alloys

The variation of thermal conductivity of solid phase versus temperature for Sn-21 wt.% Bi, Sn-25 wt.% In and Sn-35 wt.% In-26 wt.% Bi alloys were measured with a radial heat flow apparatus. From the graphs of thermal conductivity versus temperature, the thermal conductivity of the solid phases at their melting temperatures and the thermal temperature coefficients for the same alloys were obtained. The ratios of thermal conductivity of liquid phase to solid phase for the same materials were measured with a Bridgman type directional solidification apparatus. The variations of electrical conductivity of solid phases versus temperature for the same alloys were determined from the Wiedemann-Franz law by using the measured values of thermal conductivity. From the graphs of electrical conductivity versus temperature, the electrical temperature coefficients for the same alloys were also determined. According to present experimental results it can be concluded that the thermal and electrical conductivity of Sn based alloys depend on the thermal and electrical conductivity of the alloying elements. If the thermal and electrical conductivity of the alloying elements are lower than the thermal conductivity of Sn, the thermal conductivity of Sn based alloys decreases, whereas, otherwise, it increases.