Authors: Sea Hoon Lee, Hidehiko Tanaka, Toshiyuki Nishimura, Shu Qi Guo, Yutaka Kagawa
Abstract: We report sintering additive systems to decrease the densification temperature of the
corrosion resistant AlN-SiC-TiB2 system. Since oxide additives degrade the high temperature
properties of the system, and other kinds of metallic additives may affect the formation of protective
mullite during oxidation, only the constituent elements were applied as additives. Dense samples ( >
98 % relative density) could be fabricated at 1850 oC and 1900 oC by spark plasma sintering (SPS)
and hot pressing method, respectively.
1075
Authors: Li Juan Zhou, Yong Ting Zheng, Shan Yi Du, Hong Bo Li
Abstract: The fabrication of AlN-SiC-TiB2 ceramics with powder mixtures of Al, 6H-SiC and TiB2
was investigated by self-propagating high temperature synthesis (SHS) and hot isostatic pressing
(HIP). The powder mixtures were shaped by isostatic cool pressing method and the combustion
reaction was carried at the pressure of 100-200 MPa N2 by an ignitor. The compositions and
morphologies of the combustion product were studied by XRD and SEM. The determined bending
strength and the fracture toughness of the ceramics were 350 MPa and 3.5 MPa⋅m1/2 respectively.
1505
Authors: Li Juan Zhou, Yong Ting Zheng, Shan Yi Du
Abstract: AlN-SiC-TiB2 ceramics were synthesized by self-propagating high temperature synthesis
(SHS) and hot isostatic pressing (HIP) methods. The powder mixtures of Al, 6H-SiC and TiB2 were
shaped by isostatic cool pressing method, and then combustion reaction was carried at the pressure of
100-200 MPa N2 by an ignitor. The solid solution of AlN and 2H-SiC in AlN-SiC-TiB2 ceramics was
formed. The phase composition and microstructure were investigated by XRD and SEM. The
mechanical properties of composite were measured as functions of composition. The maximum value
of flexural strength and fracture toughness of composites were 430 MPa and 3.9 MPa⋅m1/2
respectively.
1517
Abstract: As-cast AM60 magnesium alloy was solid dissolved with exercising different pressures (atmospheric-pressure, 3, 4 and 5 Gpa) to it and subsequently aged for 10 h at 200 °C under atmospheric-pressure. The aging alloys were characterized by optical microscope, and their compressive properties were investigated by a Gleeble-3500 hot-stimulation machine. The results show that, compared with exercising atmospheric-pressure during solution treatment, exercising high-pressure during this process causes that the α-Mg grains of the subsequent aging alloy are more fine and uniform, while the β-Mg17Al12 phases transform into fine particles and aggregate to form gobbets or strips. With increasing the pressure gradually, the compressive strength of the aging alloy increases up to 4 Gpa and then decreases, while the maximum plastic strain decreases up to 4 Gpa and then increases.
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Authors: Taciana Regina de Gouveia Silva, Keila Machado Medeiros, Patrícia Costa Fernandes Menezes, Edcleide Maria Araújo, Tomás Jefférson Alves de Mélo
Abstract: The nanocomposites are hybrid materials where at least one of the components has nanometric dimensions and in the same way as traditional composites are formed, one of the components is the matrix in which nanoparticles are dispersed. One of the possibilities of applications of nanocomposites is to obtain polymer films for applications in the barrier, or separation promoted by the dispersion of the clay lamellae. In this work, nanocomposites of nylon 6/bentonite clay were obtained by melt intercalation. The used clay was the Brasgel PA, and quaternary ammonium salt was Praepagen-HY, used in organophilization of the clay. By XRD, it was observed the disappearance of the characteristic peak of clay, and this can be facilitate the possible exfoliation of clay in the produced films from the nanocomposite. By SEM, it was observed, an apparently dense layer with no pores.
1860
