On the basis of omega-scan x-ray diffraction (XRD), quantitative and qualitative characterization methods for fiber texture are proposed. The physical meaning of omega-scan curve is discussed in detail, and it is shown that the relative intensity curve of omega-scan XRD for a certain crystal plane is proportional to the pole density of the plane. Then qualitative and quantitative characterization methods for fiber texture are proposed from the concept of pole density. The proposed methods can be used in any crystal system. As an example for experimental verification, an orientation distribution function (ODF) experiment and a series of omega-scan XRD experiments are performed on a sputtered platinum film. From the comparison between the result of the ODF experiment and that of the analyses on the omega-scan XRD experiments, it is proved that the proposed qualitative and quantitative methods are effective and simple.

No abstract

Cu matrix composites with different volume fraction of Ag coated β-eucryptite particulates were successfully fabricated by powder metallurgy method. Low thermal expansion coefficient and high thermal conductivity were attained simultaneously in the new Cu matrix composite. The microstructure of β-eucryptite–Cu composite was studied by scanning electron microscope and transmission electron microscope. The thermophysical properties of β-eucryptite–Cu composites were analysed by means of thermal dilatometer and diathermometer. No interfacial reaction products between β-eucryptite and Cu were found in the composite. The research indicates that β-eucryptite, which has a negative coefficient of thermal expansion, is a useful reinforcement, which can remarkably reduce the coefficient of thermal expansion of Cu matrix composite. The effects of volume fraction of β-eucryptite particulates on the thermal expansion coefficient and thermal conductivity of the composite were investigated.

No abstract

ZnAl 2 O 4 -coated aluminum borate whiskers reinforced 2024Al composite was fabricated by squeeze casting. Interfacial microstructures and tensile properties of the composite were investigated. The results show that ZnAl 2 O 4 coating of the whiskers can improve the wettability of the whiskers by molten aluminum during squeeze casting, resulting in the increase of tensile properties of the composite. During thermal exposure, ZnAl 2 O 4 at the interface can effectively hinder harmful interfacial reactions, resulting in the improvement of thermal stability of the composite at high temperatures. Fracture mechanisms of the composite in as-cast and after thermal exposure were also investigated.