Papers by Keyword: In Situ Consolidation

Abstract: A novel filament winding process technology has been realized which allows to combine on-line solution impregnation with in-situ consolidation for a kind of high performance thermoplastic, poly (phthalazinone ether sulfone ketone) (PPESK). This technology solved the common problem of impregnating a large number of slender filaments with a highly viscous polymer melt which usually existed in thermoplastic manufacturing. During the winding process, the high-quality carbon prepreg tapes were firstly obtained on-line by using solution impregnation method, and then an arc electric heater was utilized to ensure the adaptable preheating and processing temperature. With the help of heat and tensile force, the intimate interlaminar contact was achieved.

Abstract: This paper reviews a method, “in situ consolidation ball milling” that provides artifactfree bulk nanocrystalline samples for several ductile metals such as Zn, Al and Al alloys, and Cu and Cu alloys. The preparation method is described in this paper and examples of the mechanical behavior of nanocrystalline materials made by this technique are given. It is found that in such artifact-free metals, combinations of both high strength and good ductility are possible.

Abstract: Cu-(2.5 or 5.0vol.%)Al2O3 nanocomposite balls and granules and Cu-(2.5vol.% or 5.0vol.%)Pb alloy powder were prepared by high energy mechanical milling (HEMM) of mixtures of Cu and either Al2O3 or Pb powders. It was observed that with the increase of the content of Al2O3 nanoparticles from 2.5vol.% to 5vol.% in the powder mixture, the product of HEMM changed from hollow balls into granules and the average grain size and microhardness changed from approximately 130nm and 185HV to 100nm and 224HV, respectively. On the other hand, HEMM of Cu–(2.5 or 5.0vol.%) Pb powder mixtures under the same milling conditions failed to consolidate the powder in-situ. Instead, it led to formation of nanostructured fine powders with an average grain size of less than 50nm. Energy dispersive X-ray mapping showed homogenous distribution of Pb in the powder particles in Cu–5vol.%Pb alloy powder produced after 12 hours of milling. With the increase of the Pb content from 2.5 to 5.0 vol.%, the average microhardness of the Cu-Pb alloy powder particles increases from 270 to 285 HV. The mechanisms of the effects are briefly discussed.

Abstract: The forming of Al2O3 ceramics was carried out by the colloidal in-situ consolidation using modified starch in this work. The effects of the modified starch content in the alumina suspensions on their rheological behavior, consolidation, microstructure and properties of the green bodies were investigated. The different shape and high relative density of ceramic green bodies were achieved by this method. The results indicated that the alumina suspensions with modified starch were easier to cast due to their low viscosity and high fluidity. After drying, the linear shrinkage of the green bodies was low, ranging between about 1.5% and 2.2% and their bulk density was higher than 57% of the theoretical density. The maximum bending strength of the dried green bodies reached to 8.2 MPa and the microstructure of the green bodies was uniform with a narrow unimodal distribution of pore size. It is concluded that the colloidal in-situ consolidation casting using modified starch can perform near-net shaping of ceramic components with high-performance and it is a potential forming technique for ceramics.