Undercooling and Wettability Behavior of Interstitial-Free Steel on TiN, Al 2 O 3 and MgAl 2 O 4 Under Controlled Oxygen
- PDF / 1,479,499 Bytes
- 10 Pages / 593.972 x 792 pts Page_size
- 18 Downloads / 170 Views
INTRODUCTION
STUDIES of heterogeneous surface nucleation in undercooled molten melts by chemical catalysts have suggested that the fine equiaxed structures could be achieved through the efficient nucleant particles such as oxides, carbides, sulfides, nitrides, etc., which were included in the liquid alloy, and the successful cases have been shown in the field of welding and casting.[1–5] Pattnaik et al.[1] dispersed fine TiB2 particles in Al-5Ti-1B alloy for nucleating fine a-Al grains. Fine equiaxed structure of Mg-Al alloy nucleated by MgAl2O4 having smaller lattice misfit with primary a-Al phase was also reported by Li.[2] In a recent article review by Fan,[3] effective grain refinement caused by inclusions could be achieved by enhancing the heterogeneous nucleation potency, in which the nucleating particles were sufficient in number, well dispersed, and of suitable particle size and size distribution. Meanwhile,
ERZHUO GAO and GE ZOU are with the School of Metallurgy and Environment, Central South University, Changsha, Hunan 410083, China, and also with the International Research Center for Clean Steel, Central South University, Changsha, Hunan 410083, China. WANLIN WANG is with the School of Metallurgy and Environment, Central South University, and also with the International Research Center for Clean Steel, Central South University, and also with the National Center for International Research of Clean Metallurgy, Central South University, Changsha, China. Contact e-mail: [email protected] FANJUN MA is with the School of Metallurgy and Environment, Central South University, and also with the National Center for International Research of Clean Metallurgy, Central South University. XUECHAO LUO is with the School of Metallurgy and Environment, Central South University. Manuscript submitted December 10, 2015. METALLURGICAL AND MATERIALS TRANSACTIONS B
a maximized solidification undercooling is desirable to allow more nuclei to initiate the crystallization. Consequently, intensive investigations also have been conducted to elucidate the fundamental phenomenon of undercooling potential necessary for heterogeneous nucleation of new crystalline phase.[6–16] The fundamental solidification model that links macroscopic heat transfer and microscopic solidification and the delta ferrite on various kinds of substrates has been conducted by Yoshioka et al.[6,7] Bramfitt[8] measured the critical undercooling of liquid iron on various carbides and nitrides and proposed that the planar lattice disregistry is an important factor affecting the degree of potency for heterogeneous nucleation. Nakajima et al.[9] employed differential scanning calorimetry (DSC) to evaluate the undercooling degree of pure iron and Fe-Ni alloy containing TiN, Al2O3, and Ti2O3 inclusions and found that the primary solid nuclei preferentially formed in the order of TiN, Al2O3, and Ti2O3 which confirmed the lowest lattice disregistry between delta ferrite and TiN substrate have the highest nucleation efficiency in triggering heterogeneous nucleation. Suzuki et al.[10] s
Data Loading...
