YIN Zhi-min, ZHU Da-peng, JIANG Feng. Recrystallization of Al-Mg-Mn and Al-Mg-Mn-Sc-Zr Alloys[J]. Journal of Materials Engineering, 2004, 0(6): 3-6.
The change of Al-Mg-Mn and Al-Mg-Mn-Sc-Zr alloys’ structures and properties after cold-rolling at different annealed temperatures was studied. The results show that adding of 0.4% (Sc+Zr) (mass fraction) can increase the recrystallization temperature by 120℃ compared with the alloys without minor Sc and Zr. The alloys with minor Sc and Zr have no obvious ending recrystallization temperature, and the microstructure remain fiber structure even at 550℃. Combined adding of Sc and Zr can form the second Al3(Sc,Zr)II particles with nanometer size. Those particles can strongly pin dislocation and subgrain boundaries, which effectively inhibit the recrystallization during annealing by inhibiting the nucleation of recrystallization and the growth of subgrains.
YOU Hong, LIU Yan, SUN De-zhi, HU Li-jiang. Study on Corrosion Resistance Properties of Organic-inorganic Hybrid Coatings on LY12 Aluminum Alloy[J]. Journal of Materials Engineering, 2004, 0(6): 7-11.
Organic-inorganic hybrid coatings modified by tetraethoxysilane (TEOS) were prepared from vinyltrimethoxysilane(VMS), [3-(methacryloxy)propyl]trimethoxysilane(MPMS) and (3-glycidoxyproyl)trimethoxysilane (GPMS) respectively. Properties of corrosion resistance were studied by potentiodynamic polarization curves. The effect of TEOS content on anticorrosion properties was tested. Salt spray test and SEM images were employed to examine the ablitity of coatings to resist long-time corrosion. The result shows that hybrid coatings are effective on inhibiting corrosion reaction. Corrosion current of VMS coating and MPMS coating is 300 times smaller than that of bare sample. The corrosion current of hybrid coatings is lowest when TEOS content is 15%~20%(mass fraction,the same below). The ability to inhibit corrosion of VMS-TEOS coatings is highest and that of GPMS-TEOS coatings is lowest. It shows that VMS and VMS+20%TEOS coatings had the strongest ability to resist salt spray corrosion. However, in general, the ability to resist long time corrosion of hybrid coatings is not very good.
JIANG Kai-yu, DUAN Xu-ming, WANG Min-jie. Influence of Technical Parameter on the Effect of RPM-CVI Technology for Carbon/Carbon Artificial Bone[J]. Journal of Materials Engineering, 2004, 0(6): 12-15,19.
Though carbon/carbon composite has excellent biologic capability, it is very difficult to be made into artificial bone that has complex shape using traditional technics. To solve this problem, a new forming technology, RPM-CVI technology, is brought forward. This technology combines rapid prototyping manufacture technology with chemical vapor infiltration technology. Artificial bone can be fabricated in shorter period.Theoretically analyze and experiments indicated that the parameters, such as porosity of the perform, volume friction of fibers, flowing direction of resin, reaction temperature and concentration of reaction gas, have important influence on the forming and densification effect of RPM-CVI process. It can enhance forming effect and shorten densification period.
GU Li-xin, JIN Jian-jun, LIU Fu-rong. The Effect of Heat Treatment on Microstructure and Mechanical Properties of 0Cr17Ni5Mo3 Steel[J]. Journal of Materials Engineering, 2004, 0(6): 16-19.
The effect of heat treatment on microstructure and mechanical properties of 0Cr17Ni5Mo3 steel was studied. It was shown that the mechanical properties were unconspicuous changing after solution treatment at different temperatures. The strength of the steel was highest when aging at 470℃.The tempered martensite embrittlement appeared at 450℃ i.e.,the impact toughness was the lowesies.
LI Xiao-jun, WU Jian-sheng, ZHANG Jing-guo, SHI Hai-sheng, LIN Yi-jian. Microstructure of a Spray-formed Ultrahigh Carbon Steel After Superplastic Deformation[J]. Journal of Materials Engineering, 2004, 0(6): 20-23.
The superplastic behavior of a spray-formed ultrahigh carbon steel (UHCS-3Si) and its microstructure after superplastic deformation were investigated. The typical microstructure of as-sprayed UHCS-3Si was fine lamellar pearlite. The lamellar peralite changed to equiaxed grains stabilized by spheroidized cementite particles distributing at grain boundary during the superplastic deformation. High density dislocation and grain deformation were observed in UHCS after superplastic deformation. The mechanism of superplastic flow is grain boundary sliding (GBS) cooperating with the dislocation creep.
LI Xiao-jun, PU Yu-ping, LÜ Guang-shu, WANG Qiang. Study on Tribology Property of Polyimide[J]. Journal of Materials Engineering, 2004, 0(6): 24-27,32.
The relation between friction coefficient(μ)and time(t) of PI sample molded by heating pressing were tested on ring-block tribology machine under different loads(P),velocities(V),and tribology laws of the changing of friction coefficient with time,load and velocity were discussed.The results show that,with the increase of V, peak of μ decreases, time of peak arriving accelerates and peak’s width become narrow in the first stage, time of arriving on the second stage brings forward. The effect of P on μ is similar to V on μ,but the effects of P on time of peak arriving and peak’s width are contrary. In the third stage, the steady value of μ doesn’t have single value relation to P or V, while have the exponent relation with unit load (p) and velocity’s product (pV,MPa·m·s-1).
HUANG Zheng-hua, GUO Xue-feng, ZHANG Zhong-ming, XU Chun-jie. Effects of Si on Microstructure and Mechanical Properties of AZ91D Magnesium Alloy[J]. Journal of Materials Engineering, 2004, 0(6): 28-32.
Microstructures and phase compositions of AZ91D alloys after adding trace Si was observed using OM and XRD, meanwhile their tensile properties and hardness at ambient temperature were tested. The fractographs of the alloys were investigated using SEM. The results show that Chinese script type Mg2Si phase is formed in the microstructures of AZ91D alloys after adding a certain quantity of Si content, which is enriched in the front edge of the solid/liquid interface. Then the free growth of α-Mg matrix is hindered and as-cast microstructures are refined. The existence of the Chinese script type Mg2Si phase can lead to the reduction of the mechanical properties of the alloys. The fractograph of AZ91D alloy is brittle fracture that is mainly composed of cleavage-type fracture, while the fracture occurs in the interface between α-Mg matrix and Chinese script type Mg2Si phase after adding Si content.
SHI Zhi-qiang, LIU Yu-hui, LI Shi-chun. Influence of Heat-treatment on Transformation Superplasticity of the as Cast Zn-5%Al Alloy[J]. Journal of Materials Engineering, 2004, 0(6): 33-36,40.
Experiment results show that Zn-5%Al (mass fraction,the same below) eutectic alloy as cast reveals superplasticity when it experiences a tensile deformation under a thermal cycling condition (20~350℃). A linear relationship between the plastic strain increment produced after one cycle and the externally applied biasing stress as the stress is less than 1.4MPa, which conforms to the prediction of Greenwood-Johnson model and belongs to the transformation superplasticity. During thermal cycling, internal-stress produces and the plastic deformation is accommodated by α/β interphase diffusion process. After quenching, the eutectic α phase in Zn-5%Al alloy is spheroidized, and the longer the holding time, the higher the spheroidization degree. Deffusional accomadation around α phase during thermal cycling is much easier for globular structure than strip, so a fast strain rate in quasi-steady state and a high rupture elongation can be gained.
LIU Hong-mei, QIU Cheng-jun, CAO Mao-sheng. Development of PZT Films in MEMS Device[J]. Journal of Materials Engineering, 2004, 0(6): 37-40.
The preparation of PZT films, the problems in fabrication, the PZT films integrated with MEMS device and the development of PZT films application in MEMS are presented in this paper. Their foreground of PZT films application is also prospected.
HUANG Xue-wen, DONG Guang-neng, ZHOU Zhong-rong, XIE You-bai. The Wear-resistance of TiNi Alloy and its Tribological Applications[J]. Journal of Materials Engineering, 2004, 0(6): 41-44,48.
TiNi alloy is an excellent tribo-material compared to conventional wear-resistant materials, which is closely related to its superelasticity originating from stress-induced matensite transformation, along with rapid strain-hardening, erosion-resistance and fatigue-resistance. From the points of mechanism, conditions as well as influence factors of superelasticity, the contributions to superior tribological performance of TiNi alloy were discussed. The measures to enhance the superelasticity and to fully exert it were summarized. The current situation of tribological applications of TiNi alloy was reviewed and research tendencies were put forward.
WANG Qing-bin, TIAN Qiu, XU Hui, ZOU Gui-zhen, CAO Mao-sheng. Progress in Nano-powder Composite Coatings[J]. Journal of Materials Engineering, 2004, 0(6): 45-48.
The preparation and classification of nano-powders composite coating, and properties such as wear resistance,antifrication,corrosion resistance, temperature tolerance, self-lubrication,catalyzing and conduction of magnetic force were reviewed, along with the co-deposition mechanism and the influencing factor of nano-powder composite coating in recent years.
