In-situ Formed AIN Particulates and TiN Whiskers Mixture Reinforced Al Composite

The TiNw-AINp/Al composite has been successfully fabricated by gas-liquid reaction method in an intensive electromagnetic mixing and casting in an appropriate cooling condition. The as-cast samples of the composite exhibit a homogeneous distribution of TiNw and AINp, and the in situ formed TiN whisker has a mean diameter of 0.5 μm and mean aspect ratio of 5.8~7.5, and the diameter of the AIN particulates is less than 5 μm. TEM observation indicates that there exist some submicron and nanometer sized in situ formed TiNw-AINp in α-Al matrix. The formation mechanism of in situ formed TiNw and AINp is also discussed

Review on Fabrication Methods of in situ Metal Matrix Composites

This paper deals with a series of novel processing techniques based on the in situ production of metal matrix composites (MMCs). In situ techniques involve a chemical reaction resulting in the formation of a very fine and thermodynamically stable reinforcing ceramic phase within a metal matrix. As a result, this provides thermodynamic compatibility at the matrix-reinforcement interface. The reinforcement surfaces are also likely to be free of contamination and, therefore, a stronger matrix-dispersion bond can be achieved. Some of these technologies including DIMOX^? XD, PRIMEX^? reactive gas infiltration, high-temperature self-propagating synthesis (SHS), and liquid-solid, or solid-gas-liquid reactions as well as plasma in situ MMCs are expressed in this paper.

The Calculations of 3-Dimensional Ising Model of Finite Width

In order to calculate 3-dimensional Ising model,we develop a method to build a much smaller transfer matrix containing the largest eigenvalue from the original 2^(N_1N_2) × 2^(N_1N_2) matrix V_1. Firstly,the transfer matrix V_1 is written as the linear combination of several basic vectors. Secondly,we divide the basic vectors into several subgroups. The multiplication of a basic vector and V_1 can be written as the linear combination of basic vectors from the same subgroup. Finally,we use a new transfer matrix V_2 to describe the relationship between basic vectors of the same subgroup.V_2 is much smaller than the original transfer matrix and contains the largest eigenvalue of V_1.We use this method to calculate the specific heat per atom Cpaand the magnetic momentum per atom Mpa. The results show that there exists a pair of temperature and magnetic field intensity where the specific heat gets to its maximum value. When N_1N_2 increases,the maximum value of specific heat becomes larger.

Electrochemical synthesis,structure characterization and magnetic properties of Tb_(x)Fe_(7)Co_(3)(x=0,0.6,0.8) nanowires

Highly ordered Tb_(x)Fe_(7)Co_(3)(x=0,0.6,0.8)nanowires were synthesized in alumina templates by electrochemical deposition method.Here,the effects of Tb content and annealing treatment on the phase composition,morphology,crystalline structure and magnetic properties were investigated.The asdeposited Tb_0 Fe_(7)Co_(3)nanowires comprise Fe_(7)Co_(3)phase.While after adding Tb,the diffraction peaks slightly shift left,indicating the infiltration of Tb atoms into Fe_(7)Co_(3)phase.After annealing,Tb_0 Fe_(7)Co_(3)nanowires still consist of Fe_(7)Co_(3)phase with a slight enhancement on coercivity.While the annealed nanowires with Tb doped present a complex phase composition containing Fe3 Tb,Fe_(2)Tb,Co_(3)Tb,Co_(17)Tb_(2),TbFeO_(3)and Fe_(2)O_(3)phases distribute in the central portion,and Co_(0.72)Fe_(0.28)at the nanowire outer walls.The annealed Tb_(x)Fe_(7)Co_(3)(x=0.6,0.8)nanowires show higher magnetic performance owing to the formation of hard magnetic phases,the interfacial elastic coupling between hard and soft phases and the coherent Fe3 Tb/Co_(3)Tb interface which restrain the domain wall motion.To be specific,the coercivity and remanence ratio of TbxFe_(7)Co_(3)(x=0.6,0.8)nanowires significantly enhance with increasing Tb content.