Abstract: There is an increasing interest in developing fully biodegradable materials for industrial
applications. Composite combining biodegradable polymer and natural fiber could be a fully
biodegradable material. This work focus on the investigation on China jute fiber reinforced PLA
composites. Composites with three different fiber volume fractions were fabricated by film stacking
hot press method. Mechanical properties have been investigated and the microstructure of the
composites was observed. Fiber surface treatment by silane was applied in order to investigate the
effects on the properties of the composites. The moisture absorption rates in a hygrothermal
environment were also measured.
Abstract: Based on Brinson’s one-dimensional thermo-constitutive law of SMA and classical plate
theory, linear non-axisymmetric vibration of uniform heated composite annular plate embedded
with circumferential SMA fibers is investigated. Natural frequencies of the annular plates with
immovably clamped boundary condition, depending on the temperature rise are obtained by using
shooting method. The characteristic curves of first four natural frequencies of non-axisymmetric
vibration versus temperature rise are plotted. Influences of the volume fraction and the initial strain
of SMA on the natural frequencies of plate are analyzed. The numerical results show that, the
activation of SMA can enhance the natural frequency both in the inverse martensite transformation
temperature range and the thermal buckling temperature.
Abstract: Adopting two-step deposition processes, SiC concentration gradient layer on the surface
of Cf/C composites were prepared via Self-heating Chemical Liquid Deposition (SHRCLD)
technique. In second deposition process, carbon and SiC were codepositted from pure kerosene and
TEOS. The temperature of deposition was 1000°C~1200°C and the system pressure was 0.1MPa.
Different thickness of gradient layers would be attained via adjusting the proportion of TEOS in
procurer and controlling deposition time. Oxidation resistance, and mechanical tests were
investigated, and the microstructure was observed under SEM. Results showed that the flexural
strength of the composites was 123.7 MPa. The antioxidation temperature of Cf/C composites with
the gradient layer is up to 800°C in air. The process of SHCLD technique is simple and easy to be
controlled, and the deposition rate is faster than other conventional technique.
Abstract: The Al2O3/LiTaO3 (ALT) composite ceramics were fabricated by hot pressing method
and polarization treated at different temperatures along height and width directions. Effects of
polarization treatment on mechanical properties of the ALT composite ceramic were investigated.
Flexural strength decreased with the increase of polarization temperature. Meanwhile, the flexural
strength of samples polarized in height direction is higher than that polarized in width direction. The
composite ceramic fractures intragranularly, and many rupture steps in polarization direction were
observed on fractographs of the composite ceramics. Domain switching in LiTaO3 particles
increased the resistance of crack propagation and improved the mechanical properties of the
polarized ALT composite ceramics.
Abstract: In the present work, a SiCp/Al composite was fabricated by pressureless infiltration of
aluminum alloy into loose-packed SiC particles preform, and its microstructure and hardness
performance were investigated. The results showed that the composite was fully infiltrated and the
particles were distributed uniformly in the composite. Interfacial reactions were found in the as-cast
composite and the reaction product was identified as MgAl2O4 by TEM observation and XRD
analysis. The interfacial reactions enhanced the wettability and promote the spontaneous infiltration
process. The thermal exposure process increased the Brinell hardness of the composite. After the
thermal exposure process, the block-like interfacial reaction products were distributed discretely, but
the amount of the reaction products was increased.
Abstract: 55vol% TiB2P/2024Al composite was fabricated by squeeze casting technology, and the
effect of heat treatment on mechanical properties of the composites was studied by means of hardness
measurement, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and
tensile testing etc. Results show that heat treatment has remarkable influence on the hardness and the
tensile strength of the composites. For TiB2P/2024Al composites, the composites aged at 130°C for 5h
can obtain the highest hardness, and the composites peak-aged at 160°C and aged at 190°C for 24h
can obtain the higher tensile strength, which is due to the type of precipitates in the composites.
Considering the experimental error, heat treatments has no obvious effect on elastic modulus of the
Abstract: MoSi2-SiC precursor powder has been synthesized via the mechanical alloy method with
the elements Mo, Si and C powder. The SiC/MoSi2 composites with different SiC volume fraction
have been prepared by reactive hot-pressing the precursor powder at 1350 °C. There is a significant
increase in the fracture toughness due to addition of SiC reinforcement. However, the intermediary
ternary phase exists in this system—namely, Mo5Si3C, Nowotny phase, which has negative effect on
the fracture toughness, and can be eliminated through high temperature treatment at 1600 °C for 2 hrs.
Abstract: Statistical diagnosis using electrical resistance changes is performed to detect a
delamination crack in a CFRP beam. This method enables to reduce data required for damage
identification. First, a new measuring method of multiple electrical resistance changes is proposed to
perform statistical diagnosis. The proposed method measures electrical resistance changes of multiple
segments in a CFRP beam although electrical interference must be considered when multiple voltages
are charged at once. Next, statistical diagnosis is performed on loading to the CFRP beam. A
delamination crack is detected by the change of relative relationship between multiple electrical
resistance changes due to damage occurring. As a result, the monitored states of the CFRP beam are
diagnosed exactly by the proposed damage detection system.
Abstract: Magnesium borate whisker reinforced aluminum alloy 2024 (AA2024) composite was
fabricated by squeeze casting method, after was CuO coating of the whisker. The interfacial
reaction in the composite was investigated. To change the interfacial reaction degree, the solution
treatment for different time was carried out. The results show that the interfacial reaction degree
increases with solution time increasing. The maximum ultimate tensile strength can be obtained
when the solution time is suitable.
Abstract: Carbides reinforced intermetallic matrix composite coatings for elevated temperature
environmental resistance were prepared on Ni-based suaperalloy substrate using CO2 laser cladding
process. The phases of clad layer were investigated by scanning electron microscopy (SEM), X-ray
diffractometer (XRD) and energy-dispersive spectrometer (EDS). The laser cladding of the
Ni78Si13Ti9/WC powder shows that the products mainly consist of TiC, WC and Ni3(Si,Ti) phases.
A chemical reaction between WC particle and Ti powder occurs during the laser process, therefore
TiC is formed. The microhardness of the samples increases with the increase of the content of WC.