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

Sn – Cd eutectic melt was first obtained in a hot filling furnace and then directionally solidified upward with different growth rate ranges (8.1–165 μm/s) at a constant temperature gradient G (4.35 K/mm) in the Bridgman-type directional solidification furnace. The lamellar spacings (λ) were measured from both transverse and longitudinal sections of the samples. The influence of the growth rate (V) on lamellar spacings (λ) and undercoolings (Δ T) was analyzed. λ2V, ΔTλ and ΔTV-0.5 values were determined by using λ,ΔT and V values. Microindentation hardness (HV) was measured from both transverse and longitudinal sections of the specimens. HV values increase with the increasing values of V but decrease with increasing λ values. λ-V, λ - ΔT and λ2V results have been compared with the Jackson–Hunt eutectic model and similar experimental results, HV - V and HV - λ results were also compared with the previous work.

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Microstructure Formation during Unidirectionally Solidified Pb-Bi-Sn Tenary Quasi-Peritectic Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.189-193.3799 ◽

2011 ◽

Vol 189-193 ◽

pp. 3799-3803

Author(s):

Xiao Wu Hu ◽

Hong Yan

Keyword(s):

Solid Solution ◽

Temperature Gradient ◽

Growth Velocity ◽

Solution Phase ◽

Solid Solution Phase ◽

Directionally Solidified ◽

Microstructure Formation ◽

Peritectic Alloy ◽

Constant Temperature Gradient ◽

Α Phase

In order to investigate the microstructure formation resulted from quasi-peritectic reaction in Pb-Bi-Sn ternary alloy, specimens were directionally solidified with a constant temperature gradient (G=18 K/mm) and the growth velocities ranging from 0.5 μm/s to 10 μm/s. Experimental results indicated that a microstructure, which is composed of the residual primary α phase (Pb-rich solid solution), peritectic β-(Pb7Bi3) phase and Sn-rich solid solution phase was observed. Transition from primary α-cell to primary α-dendrite took place with the increasing growth velocity. The rod-like eutectic was observed in the inter-cellular region under low growth velocity. Detail analyses were adopted to identify the phases and determine the phase compositions, respectively.

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Influence of Growth Rate on the Solute Distribution of Directionally Solidified Cu-Ag-Zr Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.275.192 ◽

2011 ◽

Vol 275 ◽

pp. 192-195

Author(s):

Bok Hyun Kang ◽

Woo Hyun Lee ◽

Ki Young Kim ◽

Hoon Cho ◽

Jae Soo Noh

Keyword(s):

Electrical Conductivity ◽

Growth Rate ◽

Temperature Gradient ◽

Constant Temperature ◽

Vickers Hardness ◽

Growth Rates ◽

Back Diffusion ◽

Directionally Solidified ◽

Constant Temperature Gradient ◽

Zr Alloy

Cu-2wt.Ag-2wt.%Zr alloy was directionally solidified with different growth rates(V=10-200 um/s) at a constant temperature gradient(G=3.1 K/mm) in a modified Bridgman furnace. The influence of growth rate was investigated by observing the microstructure and measuring the solutes’ compositions within the Cu-matrix and dendrite boundaries. The experimental results show that increasing the growth rate, decreased both the primary and secondary arm spacing and increased micro-Vickers hardness. The solutes’ concentration also increased as a result of the back diffusion caused by a decreasing growth rate. The electrical conductivity depends on the solutes’ distribution.

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