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The nucleation potential of transition metal (TM) carbides formed in steel can be predicted by the behavior of iron adsorption on their surface. Therefore, Fe adsorption on the (001) surface of (A1-xmx)C (A = Nb, Ti, m = Mo, V) was investigated by the first-principles method to reveal the initialization of Fe nucleation. The Mulliken population and partial density of state (PDOS) were also calculated and analyzed in this work. The results show that Fe adsorption depends on the composition and configuration of the composite carbides. The adsorption energy (Wads) of Fe on most of (A1-xmx)C is larger than that of Fe on pure TiC or NbC. The maximum Wads is found for Fe on (Nb0.5Mo0.5)C complex carbide, indicating that this carbide has the high nucleation capacity at early stage. The Fe adsorption could be improved by the segregation of Cr and Mn atoms on the surfaces of (Nb0.5Mo0.5)C and (Ti0.5Mo0.5)C. The PDOS analysis of (Cr, Mn)-doped systems further explains the strong interactions between Fe and Cr or Mn atoms.

Interfacial models of SiC/ZrB2 composite coating were studied by first-principles calculations based on density functional theory (DFT). The cubic SiC and hexagonal ZrB2 were selected in our work, and twelve types of SiC (111)/ZrB2 (0001) interface structures were investigated in consideration of four different terminations and three stacking sequences. The cohesive energy (Wad), interfacial energy (γint), and electronic structure of the SiC/ZrB2 interfaces were all calculated. The results show that the ZrB2 (0001) surface with 9 layers exhibits bulk-like interior characteristic. Among the interfaces of C/Zr terminated hcp-stacked (CZH), Si/Zr terminated hcp-stacked (SZH), C/B terminated center-stacked (CBC) and Si/B terminated center-stacked (SBT), the CZH interface has the largest Wad (6.28 J/m2) and thus is of the best stability. Over the range of zirconium chemical potential, the γint of CZH, SZH, CBC and SBT interfaces are −0.31–2.50 J/m2, 1.07–3.88 J/m2, 2.85–5.66 J/m2 and 2.32–5.13 J/m2, respectively. The calculated electronic properties reveal that, the CZH, CBC and SBT interfaces mainly contain covalent bonding, while the SZH one primarily consists of metallic bonding.

Three Cu(I)-cyanide coordination polymers based on trigonal 1,3,5-tris(1H-imidazol-1-yl)benzene (tib) ligand, namely [Cu 3 (CN) 3 (tib)] n ( 1 ), [Cu 4 (CN) 4 (tib)] n ( 2 ), and [Cu 2 (CN) 2 (tib)] n ( 3 ), have been prepared and characterized by elemental analysis, IR, PXRD, thermogravimetry and single-crystal X-ray diffraction analysis. Complex 1 displays a 3D metal-organic framework with nanosized pores. Complex 2 is a 3D coordination polymer assembled by three μ 2 -cyanides and a μ 3 -cyanide with a very short Cu(I)···Cu(I) metal bond(2.5206 A). Complex 3 is a 2D coordination polymer constructing from 1D Cu(I)-cyanide zigzag chain and bidentate tib spacer. Three Cu(I) complexes are thermally stable up to 250–350 °C. Complexes 1 – 3 show similar orange emission band at 602 nm originating from LMCT mechanism.

Hydrothermal reactions of AgNO3, K3[Fe(CN)6] with N-heterocyclic ligands afforded three novel Ag(I)–cyanide coordination polymers, [Ag2(CN)2(tpt)]n (1), {[Ag(CN)(bpe)0.5][Ag(CN)]}n (2) and [Ag(CN)(btmb)0.5]n (3) (tpt = 2,4,6-tris(4-pyridyl)-1,3,5-triazine, bpe = 1,2-bis(4-pyridyl)ethane, btmb = 1,2-bis(1,2,4-triazol-1-ylmethyl)benzene). In complex 1, two Ag(CN) linear chains are bridged by bidentate tpt ligand to form a ladder-like structure, which are further connected by Ag Ag metal bond to generate a 2D polymeric network. Complex 2 is an interesting 3D supramolecular architecture assembled by 2D [Ag1(CN)(bpe)0.5]n network and linear [Ag2(CN)]n chain combined by strong Ag Ag metal bond. Complex 3 is a 1D ladder-like double-chain polymer constructed from Ag–cyanide linear chains and btmb spacer, which is further extended to a 2D supramolecular network by Ag–Ag weak interaction. The Ag–Ag metal interactions play important roles in the construction of three coordination polymers. Complexes 1 and 2 are respectively thermally stable at 300 and 180 °C. Complexes 1 and 3 emit strong blue luminescence.

The hypoeutectic Al-Si alloy billet with non-dendrite was reheated to meet the needs of the semi-solid thixoforming microstructure by four kinds of reheating power, achieving the same final temperature of 851 K. Subsequently, under the same condition of thixoforming, the microstructure, surface hardness and tensile properties were observed. Afterwards, quantitative analysis was made for the microstructures of the reheated semi-solid of billet and the thixoforming parts. The results show that when the induction reheating power is 90 kW, the average grain size of the semi-solid billet is the minimum, the microstructures of the thixoforming samples also are the finest, and the mechanical properties of the relevant thixoforming samples are the best. Furthermore, after studying on the relationship between the microstructures of the semi-solid billet of aluminum alloy and the mechanical properties of the thixoforming samples, the reverse design of microstructure is primarily achieved. Finally, the effectiveness of the reverse design for semi-solid microstructure is confirmed by an actual automobile part with complex shape.

It is shown from experiment that the pure B contained salt exhibits little refining effect, while the pure Ti contained salt, especially the salt containing 5Ti/1B, shows obvious refining effect on the pure aluminum. Crystallographic study indicates that Al 3 Ti particle is a more suitable nucleation site for the aluminum matrix than (Ti, Al)B 2 type particles (TiB 2 , AlB 2 and (Ti, Al)B 2 ), because there exist more coherent planes with aluminum matrix in the former. Thermodynamics estimation, X-ray diffraction (XRD) and SEM detection show that the refining mechanism of (Ti, B)-contained refiners is mainly contributed to the heterogeneous nuclei of fine Al 3 Ti particles dispersed in the melting, which comes from the reaction between the Ti and aluminum. (Al, Ti)B 2 type particle shows little or no direct refining effect, but it will reduce the size of Al 3 Ti since the Al 3 Ti nucleates and grows along the (Al, Ti)B 2 type particle interface.