GAO Wan-fu. Effect of Prestrain on the Reverse Martensitic Transformation of TiNi Fibers Embedded in Al Matrix[J]. Journal of Materials Engineering, 2006, 0(6): 3-4,53.
The effect of prestrain on the reverse martensitic transformation of TiNi shape memory alloy fibers embedded in an Al matrix has been studied by differential scanning calorimeter(DSC),X-ray diffraction(XRD) and scanning electron microscope(SEM) methods.The results showed that two kinds of reverse transformation occurred in the TiNi fibers after prestrain.One was the reverse transformation of the thermal-induced martensite(TIM),and the other was that of the stress-induced martensite(SIM).The reverse transformation starting temperature of TIM in the prestrained specimen was identical to that in the un-prestrained specimen.The reverse transformation starting temperature of SIM increased with increasing prestrain.The fractions of TIM and SIM that participated in the reverse transformation decreased with increasing prestrain.
LIANG Zi-qing, TANG Bang-ming, LI Yan-liang, YI Xiao-su. Study on the Compressibility of Fabric Preforms[J]. Journal of Materials Engineering, 2006, 0(6): 5-8,45.
The compressibility of fabric preforms,involved in the fiber volume fraction(Vf) in the compress process,was studied.It was found that the response behavior of tackified fabric under compression changed with the number of fabric layer and tackifier contents.Increase of the layer number and decrease of the tackifier contents led to higher Vf in the process.After compaction,there is no obvious relationship between layer number and the final compaction Vf of tackified fabric,which still influenced by tackifier contents.
YU Qian, SONG Jin-xia, WANG Ding-gang, QU Shi-yu, LI Qing. Effect of Recycled Alloy Proportion on Microstructure and Mechanical Properties of Ni-based Superalloy K465[J]. Journal of Materials Engineering, 2006, 0(6): 9-12,39.
The effects of application of recycled scraps on the composition,microstructure and mechanical properties of K465 alloy were studied.The results show that the compositions of recycle master alloy are similar to that of the fresh alloy.The addition of recycled scraps has no obvious effect on γ′ phase.However,the size and amount of microporosity increase with the recycle material proportion,and the microporosity in 100% recycled alloy is much more than that in the virgin alloy.The carbides in recycled alloy are bone-like,except that in 100% recycled alloy are particle-like.It should be noted that the morphologies of carbides may be affected mainly by solidification condition.When the recycle material proportion is less than 80%,the high temperature stress rupture properties and tensile strength at room temperature.of recycled alloy are almost equivalent to that of the fresh alloy,while tensile elongation at room temperature.of the former is lower than that of the later.However,the mechanical properties of 100% recycled alloy decrease obviously in contrast with the virgin alloy,and its high temperature stress rupture life and tensile elongation at room temperature.could not meet the demand of specifications.
CHEN Xu-dong, CUI Yan. Preparation of SiCp/Al Composites with Different SiC Volume Fraction and Compositional Graded SiCp/Al Composites by Pressureless Infiltration Processing[J]. Journal of Materials Engineering, 2006, 0(6): 13-16,39.
Using SiC particles with different diameter,by effectively controlling the distribution of SiC particles,SiCp/Al composites with different SiC volume fraction(15%~65%) were fabricated under pressureless infiltration processing.In addition,compositional graded SiCp/Al composites were also fabricated in the same way.The microstructure of SiCp/Al was studied by means of OM,XRD.Besides,density test and mechanical test were carried out on selected SiCp/Al composites.According to the study,SiCp/Al composites with different SiC volume fraction by pressureless infiltration possess have even and compact microstructure as well as fine mechanical property.Moreover,the interface between layers of compositional graded composites integrates well and there is no delamination.
LI Yuan-zhen, YUAN Li, JI Shuang-ying. Study on Optical Reflector CF Fabric/PEEK Thermoplastic Composites[J]. Journal of Materials Engineering, 2006, 0(6): 17-19,66.
The carbon fabric reinforced thermoplastic polyether-ether-ketone(PEEK) resin matrix composites has been studied and experiments of the mechanical properties,some important space-environment properties and optical reflecting properties of the composite has been carried out.The results show that the carbon fabric reinforced PEEK composites have more excellent mechanical and space-environment properties,CVCM is 0,WVR is 0.08%,test in 1×10-3Pa vacuum.A reflector(φ128mm) is made and reflectivity is 96.89%.So,this composite is an excellent high performance composite,which was suitable for service in space environment.
YU Yu-qiang, ZHANG Zuo-guang, TANG Bang-ming, LIANG Zi-qing. Study on Capillary Pressure of Fabric Preforms[J]. Journal of Materials Engineering, 2006, 0(6): 20-23,32.
The capillary experiments of three different kinds of fabrics with different tackifier contents and volume fraction of fibers(Vf) were conducted.The analytical values of capillary pressure and fiber permeability were estimated by non-linear regression method based on Darcy′s law.The effects of the tackifier and Vf on the wicking performance in these three different kinds of fabrics were investigated from the experimental data.The experimental data suggest that the permeating rate is mainly decided by capillary pressure,the permeability of these three kinds of fabrics decreased linearly with Vf in this experimental range of Vf,the permeating rate and capillary pressure decreased with the increase of Vf before Vfc but increased with the increase of Vf after Vfc;the introduction of tackifier reduced the capillary pressure of fabrics but its effect on permeability depends on the architectures of fabrics.
GUO Yun-qiang, ZHANG Ke-shi, GENG Xiao-liang, LIU Qin, QIN Liang. Effect of Substrate Performance on the Indentation Response of Coated Systems[J]. Journal of Materials Engineering, 2006, 0(6): 24-27.
The indentation response of coating-substrate is investigated using finite element analyses.The effect of substrate’s yield strength on load-displacement curve is revealed.On the certain conditions,these load-depth curves present deviation at 12%~16% of coating thickness.The results showed that substrate’s properties have a negligible effect on the indentation response when indentation displacement is less than 10% thickness of coating.Otherwise,the substrate’s plastic deformation can have serious influence.Meanwhile,this paper revealed that while yield stress is less than 2000MPa,the increasing in substrate’s yield stress can influence indentation response;on the contrary,if yield stress of the substrate is higher than 2000MPa,load-displacement curve has no change when altering substrate’s yield strength.
ZENG Jing-cheng, YIN Chang-ping, LIU Jun. Fabrication of the Cabin Component by Flexible-mould Assisted RTM Process and Its Performance[J]. Journal of Materials Engineering, 2006, 0(6): 28-32.
Some equipment components with large size and complicated internal structures were difficult to be manufactured integrally in one time by traditional RTM process.These components fabricated by traditional RTM had poor mechanical properties because the fiber volume fraction was very small.In this paper the complicated flexible-mould was fabricated with silicone rubber.The silicone rubber mould was used to assist RTM to manufacture the cabin component.The surplus resin were squeezed out when the flexible-mould expanded by heating,therefore the fiber volume content of the composites reached 57% and the mechanical performance of the composites improved much.The static mechanical properties of the cabin satisfied the requirements of the primary load bearing structure in aerospace,so the flexible-mould assisted RTM process that was suitable to manufacture the components with complicated inner shape was prosperous in fabricating equipment components.
XUE Ming, CAO La-mei. Effect of Mullite on High Temperature Anti-deforming Capability of Alumina-based Ceramic Core[J]. Journal of Materials Engineering, 2006, 0(6): 33-34,57.
The effect of mullite content and microstructure on high temperature anti-deforming capability of alumina-based ceramic core was investigated.The results show that superior heat intensity properties of alumina-based ceramic core resulted from crystal group of mullite at high temperature.
LU Jin-tang, CHE Chun-shan, KONG Gang, XU Qiao-yu, CHEN Jin-hong. Effect of Electrodeposited Ni Layer on the Galvanized Coatings of Reactive Steels[J]. Journal of Materials Engineering, 2006, 0(6): 35-39.
Four types of steels containing 0.04%,0.09%,0.14% and 0.36%Si were electrodeposited 3μm nickel layer and then galvanized in molten Zn at 450℃ for various periods of time respectively.Formation and growth of intermetallic compound layers on the surface of the specimens were investigated.The results show that the method of Ni-electrodeposited pretreatment can distinctively restrain the over-growth of the galvanized coatings of reactive steels and get eligible coatings with proper thickness,bright appearance and good adherence.EDS results show that a series of Ni-Zn alloys γ′,γ and δ2 were first formed on the surface of the samples.With prolonged immersion time,the Γ2-Fe-Zn-Ni and δ-Fe-Zn were formed accompanied by the gradual disappearance of γ′,γ and δ2 layer.After longer immersion time,the lumpy ζ-Fe-Zn occurred between δ and liquid Zn and the Г-Fe-Zn did between steel substrate and δ.Subsequently,ζ was in the form of a continuous and compact layer.The method of Ni-electrodeposited pretreatment changed the formation of Fe-Zn intermetallic compounds.The growth of ζ was greatly delayed,therefore the abnormal growth of the galvanized coating of reactive steels was eliminated.
LI Bo-yu, DONG Xing-long, LIU Yuan-yuan, YANG Ming-chuan, LIU Fang-jun. Microstructure and Formation Mechanism of Nanostructured WC-12Co Coatings Deposited by Plasma Flame Spray[J]. Journal of Materials Engineering, 2006, 0(6): 40-45.
The precursor of WC-12Co nano-composite powder is synthesized by the larruping method of spray drying and fixed bed technique,nanostructured WC-12Co cermet coatings are deposited by plasma flame spray.Microstructure of nanostructured WC-12Co cermet coatings is evaluated by using X-ray diffraction(XRD),scanning electron microscopy(SEM) and transmission electron microscopy(TEM).The nano-composite WC-12Co powders generally contain WC and Co,whereas the phases W2C,W and Co3C,Co3W9C4,Co3W3C/amorphous binder phases based on Co and nano-twins occur in coatings,the mechanism of formation of nanostructured WC-12Co cermet coatings is discussed on the basis of the microstructure in this paper.
YAO Jun-chen, WEN Li-fang, HAN Shou-bo, MA Yue. The Dynamic Mechanical Properties of Damping Aluminum Alloys Under High Strain Rate[J]. Journal of Materials Engineering, 2006, 0(6): 46-48,67.
The dynamic mechanical properties of two kind of high damping materials were studied under high strain rate.Separated Hopkinson pressure bar was used to perform the compressive test.Stress and strain curves were obtained at three different strain rates,140,275 and 500s-1.The corresponding results derived were compared with those of cast aluminum ZL101A alloy.It is shown that the dynamic mechanical properties of the two kinds of high damping materials are much better than that of ZL101A alloy.FMS0714/y(Zn-30Al) alloy exhibited the excellent dynamic mechanical property.With increasing strain rate,the elastic modulus and stress of X7093/y(Zn-30Al)alloy somewhat decreased.
ZHANG Guo-dong, LIU Shao-lun, HE Yu-huai, ZHOU Bo-zhuo. The Effect of Hold Time on Life and Behavior of Thermal-mechanical Fatigue in DS Superalloy DZ125[J]. Journal of Materials Engineering, 2006, 0(6): 49-53.
The thermal-mechanical fatigue behavior of DS superalloy DZ125 was studied.A basic cycle has been used without hold time and with hold time at high temperature to simulate only the transient behavior of critical part of a blade. Both triangular and trapezoidal wave shape signals with in-phase cycle and at maximum and minimum temperature of 550℃and 1000℃ respectively.The ratio Rε of minimum to maximum strain is-1.0.At the same strain amplitude,it was found from test that the TMF life of in-phase cycle with triangular wave shape is longer than that of in-phase cycle with trapezoidal wave shape.Also the effect of hold time on cyclic stress response under conditions of triangular and trapezoidal wave shape was studied.The thermal-mechanical fatigue damage was discussed. The results show that fatigue,creep and oxidation damage always developed during TMF.Fracture is mainly intergranular and transgranular under conditions of triangular wave shape.The path of crack initiation and growth is transgranular under conditions of trapezoidal wave shape.
LIAO Xiao-ling, LI He-jun, LI Xin-tao, HOU Dang-she. Flexural Behavior of 3DC/C Composites[J]. Journal of Materials Engineering, 2006, 0(6): 54-57.
Flexural behavior of three dimensional carbon/carbon composites(3DC/C composites)was researched using a three-point bend test,and analyzed the influence of density and braided structures on the mechanical properties and fracture modes.The results show that the density has a great impact on the strength and the modulus,and the fracture modes of 3DC/C composites change from shearing failure to tensile breakage with increasing densification degree.
NIE De-fu, ZHAO Jie, MO Tao. Room Temperature Creep and Its Effect on Flow Stress in X70 Pipeline Steel[J]. Journal of Materials Engineering, 2006, 0(6): 58-61.
The phenomenon of room temperature creep(RTC) deformation and its effect on subsequent flow stress under various loading stress rate(Lsr) and loading process in a X70 pipeline steel were studied.The experiments were performed on a MTS 810 testing machine by using standard round tension specimens.According to the results,significant time-dependent deformation under constant load was observed in this steel at room temperature,and the deformation was strongly dependent on loading stress rate and loading process.It was also found that the occurrence of room temperature creep obviously enhanced the subsequent flow stresses.Model based on dislocation theory was applied to explain the mechanism responsible for the behavior.
JU Yi, LI Zong-quan. Research Development of TiN Multi-elements Alloying Coatings[J]. Journal of Materials Engineering, 2006, 0(6): 62-66.
Multi-element alloying is one of the methods to improve the properties of TiN coatings,which has been widely investigated.The new development and trends of the researches on multi-elements alloying coatings have been introduced.The processes,structure and properties of the multi-elements alloying coatings of Ti(CxN1-x),(Ti,Al)N,(Ti,Nb)N,(Ti,Cr)N,Ti-Si-N,Ti-B-N,Ti-C3N4 have been described.The perspective of the related research has been given.
