文章信息/Info

Title:

Application of Alternative Electromagnetic Field in Crystal Growth and Solidification

作者:

伍  平; 王  勃; 王曉東

中國科學(xué)院大學(xué)

Author(s):

Wu Ping;  Wang Bo;  Wang Xiaodong

University of Chinese Academy of Sciences

關(guān)鍵詞:

微重力; 洛侖茲力; 電磁場; 強迫對流; 凝固

Keywords:

Microgravity;  Lorentz force;  Electromagnetic field;  Forced convection;  Solidification

DOI:

10.7502/j.issn.1674-3962.2017.12.05

文獻標志碼:

A

摘要:

在合金凝固過程中施加時變電磁場，導(dǎo)電熔體在洛侖茲力的驅(qū)動下產(chǎn)生的強迫對流可有效控制合金溶質(zhì)的再分配過程。在材料凝固與晶體生長過程中施加電磁場有助于深入研究其熱物理性質(zhì)、相平衡、亞穩(wěn)態(tài)、組織形成、成分過冷和形核。人們在重力環(huán)境下對合金的凝固過程已進行了大量深入詳盡的實驗探究，利用電磁場手段對凝固前沿進行有效干預(yù)并在晶體組織結(jié)構(gòu)、成分偏析等方面取得了一定的進展。而微重力環(huán)境下浮力對流減少，為在宏觀和微觀尺度上獲得成分更為均勻的半導(dǎo)體或合金材料提供了一個獨特的平臺，目前的研究表明在微重力環(huán)境下合金的凝固特征與在重力環(huán)境下的有所不同。本文從理論與實驗的角度闡釋了在微重力及重力環(huán)境下電磁場引起的強迫對流強度及方向?qū)�晶體生長過程中的宏觀偏析、微觀偏析、晶體形態(tài)以及金屬間化合物的生長模式及空間分布的影響規(guī)律。

Abstract:

In the solidification process of alloy, forced convection produced by time-varying electromagnetic fields can effectively control the redistribution process of alloy solute. The application of electromagnetic field in the solidification and growth process of materials can be conductive to the research of its thermophysical properties, phase equilibrium, metastable state, microstructure formation, component undercooling and nucleation. The solidification process of the alloy has been studied in details in the gravitational environment. The electromagnetic field method has been used to intervene the solidification front effectively and some results have been obtained in the crystal structure and segregation. Microgravity conditions provides a technique for obtaining semiconductors or alloys with more uniform composition at both macroscopic and microscopic scales. The current research shows that the solidification characteristics of the alloy under the microgravity environment are different from the gravitational conditions. In this paper, the effects of forced convection on the macro-segregation, micro-segregation, crystal morphology and the growth pattern and spatial distribution of intermetallic compounds in the process of crystal growth are discussed in terms of the theoretical and experimental perspectives.