Papers by Keyword: Peritectic Reaction

Abstract: Microstructure evolution that exhibit from the reaction of Sn Cu pritectic alloys become an interesting phenomenon that need to be explored since the properties of the alloys depend on their microstructures. Due to less understanding on the solidification behavior on peritectic alloys, extensive research are made on this type of alloys to gain more information regarding on the microstructure formation. This paper reviews the mechanisms on peritectic solidification on Sn Cu based peritectic alloys. The changed in peritectic microstructure due to external source such as direct current (DC) field, ultrasonic field and isothermal time are discuss respectively through this paper. The focus is made on peritectic solidification of Sn Cu based alloy since it has a promising potential for high temperature lead-free solder application.

Abstract: The δ→γ phase transformation in the steel was studied in detail, and the relationship between δ→γ phase transformation and the crack formation in continuous casting slabs was discussed as well. The results indicate that the micropores are formed at the positions where δ-phase transformation terminates during the δ→γ phase transformation for low-carbon non-peritectic steel. The micropores will also be formed at the positions where the peritectic reaction of the steel terminates, then the pores are remained on the grain boundary of γ-phase when γ-phase becomes granulated. The micropores distributing on the grain boundary of γ-phase is one of the results for the crack formation of continuous casting slabs and the obvious plasticity decrease of δ-phase zone in the steel. The theoretical analysis results are basically consistent with the experimental results.

Abstract: The effect of different aluminum content on peritectic reaction and mechanical properties of pentatomic TiAl-based alloy was investigated. The results indicate that the grain size gradually increase with increasing content of aluminum and addition 45.7% aluminum in TiAl-based alloy results in that the peritectic reaction can increase grain size greatly, respectively. The content of aluminum can increase the room temperature strength, high temperature strength but peritectic reaction can effectively reduce tensile strength. Aluminum content has a little effect on the ductility. The stress rupture life has positive correlation relationship with the content of aluminum.

Abstract: Porous Al-5mass%Ti alloys were fabricated using a continuous casting technique in a hydrogen atmosphere, and the effects of transfer velocity (V) and the peritectic solidification process on the pore morphology and matrix microstructure were examined. In the case of V = 0.5 mm/min, columnar microstructure and directional pores grow along the transfer direction. The Al3Ti phases are formed in localized regions of matrix part, and however, they do not suppress the growth of directional pores in the other regions. In the case of 5.0 mm/min, because needle-like Al3Ti phases grow along the transfer direction, directional pores can grow between them. On the other hand, in the case of 10.0 mm/min, spherical pores surrounded by equiaxed peritectic microstructure and homogeneously distributed Al3Ti phases are formed, because the primary α -Al and Al3Ti phases probably prevent the growth of directional pores.

Abstract: The automotive industry is increasingly utilizing advanced high-strength steels, primarily to reduce the mass of motor vehicles. However, many of these steels fall within the peritectic composition range, which are notoriously difficult to cast by continuous casting techniques. Against this background, a brief review is given of our current understanding of the peritectic reaction as such and the subsequent peritectic phase transformations.

Abstract: The microstructure evolution of Ti-Al peretectic system in transient stage and steady state in directional solidification was predicted via theoretical analysis. The solute distribution controlled by diffusion at and ahead the solid-liquid interface will determine whether the properitectic and peritectic phases can nucleate and grow ahead of the opposing solid phase. The formation of banding structure is possible in a certain composition range. At the steady state, a microstructure selection map was set up based on interface response function model. The microstructure of TiAl alloys with different aluminum content was studied with Bridgman directional solidification method. Some evidence in the experiment has been found to support the theoretical prediction.

Abstract: The macrosegregation is one of the most recurrent phenomena in continuous steel casting of slabs. It often impedes the further processing and has detrimental effect on the quality of rolled strip. The macrosegregation can be explained by the interpretation of unit steps of solidification in continuous casting slabs as well as on the basis of the interaction of the inclusions at the interface of solid and liquid phases. Development of solid shell and interaction between growing dendrites and MnS segregation has been presented. Only the pushing effect could be the real cause of MnS segregation among the three possible interactive mechanisms. The sulphur print could give misleading information on sulphur segregation.

Abstract: An Al foil of 25 µm thickness was used to produce a Ni/Al/Ni interconnection under isothermal conditions at 680°C. After dissolution of the Al filler metal in the Ni substrate, and Ni from the substrate in the Al liquid foil, a solidification process occurred. First of all, the solidification was stopped just at the disappearance of the Al liquid metal, but also at different steps of the progress of solidification. Sub-layers of the two phases Al₃Ni₂ and Al₃Ni were revealed within the frozen joints. A solidification - segregation model was developed to describe the formation of the sub-layers of both mentioned phases. The model is able to predict solute segregation profiles across the sub-layers of the Ni/Al/Ni interconnection, taking into account a superposition of some phenomena like partitioning, back-diffusion into the solid and peritectic reactions. The value of the diffusion coefficient into the solid for the Al₃Ni₂ phase formation in the presence of the liquid is also estimated.

Abstract: The aim of this study is to investigate the effect of the chemical composition, the nature of the primary solidification and peritectic reaction on microsegregation in cast steels. For this purpose, binary and ternary alloys in the Fe-Ni-C system have been selected. This study was carried out in parallel with a modelling work [1] in order to improve the prediction of macrosegregation of cast steels products.