Structures used in aerospace are influenced by temperature. So coefficient of thermal expansion (CTE) is not only an important parameter of materials, but also a significant parameter of structural design of spacecrafts with high dimensional stability. In this paper, based on the analysis of the data from tests, theoretical formulae for predicting CTE and mechanical properties of hybrid composites are presented, and the calculation program is compiled. All the equations are verified by experiments. Optimization is conducted by computer. The results and methods presented in this paper can be used both in optimal design of hybrid composites with zero CTE and in design of hybrid composites with any certain CTE value

Scanning tunneling microscopy (STM ) has been first employed to study the surface relief accompanying bainite transformation in a Fe-2.17C-12.18Cr-0.31Si-0.26Mn (wt pct) steel. With the exclusive vertical resolution of STM, we observed that the surface relief associated with bainite is a group of surface reliefs related to subplates, subunits and sub-subunits. As a whole, the relief group is in a tent shape, not of invariant plane strain (IPS) type, which is obviously different from that of martensite, and implying that bainite is not formed by shear mechanism. The fine structure of bainite in Fe-1.0C-4Cr-2.0Si (wt pct) alloy has also been studied with STM and TEM. It is found that the bainite plate is composed of subplates, subunits and sub-subunits. On the basis of the fine structure inside a bainitic ferrite plate observed under STM, a sympathetic-ledgewise mechanism of bainite formation is proposed

Grinding-induced tm phase transformation and the resultant texture in ceria-yttria-doped tetragonal zirconia polycrystals with varied tetragonality have been studied by XRD. It is observed that the reversible tm phase transformation occurs during grinding and the intensity ratio of I(002)t/I(200)t increases with the transformability. The author proposes that the texture induced by grinding at low temperatures is due to the tetragonal variant reorientation via cyclic,reversible tm phase transformation, termed "transformational domain switching", instead of the ferroelastic one

Residual electrical resistivity due to short-range order has been calculated for Cu100-xAlx (x=9.13,13.56, 14.5 and 14.76 in at pct) alloys using pseudopotential approach, and the results have been discussed in the light of experimental studies of the local-order structure of these alloys. In case of Cu85.5Al14.5, change in the total residual electrical resistivity due to neutron-irradiation effects has been estimated by including contributions from the short-range order and static atomic displacement correction. Our results show a decrease in the residual resistivity in the irradiated Cu-Al solid solution as compared to the unirradiated sample. This is in accordance with the experimental results

Corrosion inhibition of Al and Al-3.5Mg alloy by organic compounds, namely chalcones in hydrochloric acid solutions has been investigated by rapid polarization technique and weight loss method. Polarization measurements show that, the inhibitors act cathodically both in case of Al and Al-3.5Mg alloy. It was found from the weight loss measurements that, the inhibition efficiency depends on the substituent in the chalcone compound. The relative inhibitive efficiency of these compounds has been explained on the basis of structure dependent electron donor properties of the inhibitors and the metal inhibitor interaction on the surface. The inhibition efficiency ranges from 16 to 64% for Al and from 30% to 91% for Al-3.5Mg alloy

A large quantity of laminated fine grain zones were observed in the Al-Mg-Li alloy weld metal by manual TIG, which was not found in ordinary Al alloy welds. The fine grain zone is formed because of the Al3(Zr,Ti) particles in the filler metal and the manual filling of filler metal in welding process

The recrystallization behaviour of cold drawn MP159 alloy was investigated by optical and TEM examinations. It is found that the platelet ε phase in the MP alloy inhibits the recrystallization,and this effect makes the MP159 alloy with high recrystallization temperature of about 920℃.This inhibition mainly comes from the increasing of the interfacial energy, which results from the change of the coherent interfaces of (0001)hcp//(111)fcc into the incoherent interfaces when the recrystallizing grain fronts bypass the platelet ε martensite. The increasing of the interfacial energy also causes the dissolution of a few segments on the ε martensite platelets, which decreases the strength of the MP alloy

A simplifled regular solution model for the solubility of nonmetallic element (2) in metal(1)-metal(3) alloy system has been derived and applied to the Fe-C-j, Ni-C-j and Fe-N-j (j denotes a metal) systems with satisfaction. The exchange energies of concerned systems are evaluated

The erosion behaviour of TiNi alloy foils (Ni: 50.5 at pct, thickness: 70~90μm) under various heat treatments has been studied with two different tests: sand-blasting erosion (SBE) with impingement angle of 30°and slurry erosion (SE). The erosion resistance of the foils aged at 400~450℃/30 min is the best in all tests. The quenched foil is also good in the SBE test, but not so good in the SE test. The slurry-erosion resistance of the aged foils is better than that of L214 with high hardness. All the foils exhibit much better erosion resistance than 18Cr-8Ni stainless steel in the tests

The transient current behaviour for Iron in 3.5%NaCl and 3.5%NaCl +1%NaNO2 solutions during corrosion fatigue (CF) process has been investigated at different given strain amplitudes and strain rates. The results show that elastic strain has little contribution to material dissolution. The elastic tension strain results in the decrease in the transient current, while the elastic compression strain increases the transient current. Compared to the elastic deformation, plastic deformation affects material dissolution evidently For iron in 3.5%NaCl solution, the strain amplitude plays a dominant role in the dissolution process accelerated by the plastic strain, while in 3.5%NaCl+1%NaNO2 solution, both the strain amplitude and strain rate play an important role in this process. In this paper, the effect of the elastic deformation on the material dissolution and the relation between the tension and compression current peak values under the plastic cycle deformation are discussed

The random closed packing fraction of hard balls of three different sizes were measured by use of the Archimedes method. This packing fraction increases as the kind of balls with different sizes increases. The packing fraction is related to the mixing entropy of an ideal solution in respect to the holes among the hard balls. The composition zone of La-Al-Ni amorphous alloy made by cooling the alloy melt with a cooling rate of 90 Ks-1 is located at same zone of the largest values of packing fraction and mixing entropy of hard balls in the ternary system. where the proportion of atom sizes of La, Al and Ni is similar to that of hard balls. The packing fraction and the mixing entropy are qualitatively considered as one of the criteria of the glass forming ability of alloys

A transparent bulk sodium borosilicate gel with the composition of 72SiO2·23B2O3·5Na2O (wt pct) was prepared by using tetraethyl orthosilicate, boric acid, sodium methoxide, sodium alkoxide, sodium acetate as precursor, methanol, ethanol and glycolic methyl ether as precursor solvent and hydrochloric acid as catalyst. Properties of gel, varied principle and related mechanism of conversion for sol to gel are discussed. Ideal composition and dry process are given in this work

The microwave radiation method was introduced to prepare the Fe_2O_3/SO solid superacid.Its structure and properties were investigated by means of X-ray diffraction and infrared spectrum analyses as well as measurement of magnetic susceptibility and rate of esterification. The structure of the superacids prepared in microwave field can be crystalline or non-crystalline, the latter has not been reported yet in literatures. Comparing with the traditional superacid, the non-crystalline Fe2O3/SO superacid prepared in microwave field has the highest magnetic susceptibility and catalytic activity. The di-coordination of Fe2O3 and SO and the S=O bi-bond were reinforced by microwave radiation, which is favorable for increasing the acid intensity of the Fe2O3/SO catalyst

C-N thin films have been prepared by ion beam sputtering using pure N2 as discharge gas. The ratio N/C of the films measured by Auger spectrum is 20% on an average. The results of X-ray diffraction and transmission electron microscopy show that β-C3N4 phase exists in the films. Xray photoelectron spectroscopy shows that nitrogen is mostly combined with carbon with triple (C=N) and double (C=N) bonds. The IR absorption shows an absorption bond near 2185 cm-1assigned to the C=N, no trace of C-C bond was observed

This paper reports the kinetic process of Ag ion exchange for the polycrystalline Na-β"-Al2O3.The interdiffusion coefficients in the process of Ag+ and Na+ ion exchange have been calculated with an "one dimensional double side diffusion model". Microstructures of the samples were observed and analysed by XRD, EMPA, SEM. The results of the conductivity measurements for samples with Na+, Ag+ and Na+-Ag+ mobile ions are presented and explained

Applying the concept of multirange fractals, a new explanation to the Williford's multifractal curve on the relationship of fractal dimension with fracture properties in materials has been given. It 5hows the importance of factorizing out the effect of fractal structure from other physical causes and separating the appropriate range of scale from multirange fractals