ZHAO Xin-qing. The Thermodynamics of Homogeneous Martensitic Nucleation in Iron Based Alloys[J]. Journal of Materials Engineering, 1999, 0(11): 3-5,28.
On the basis of classical nucleation theory,the thermodynamics of martensitic nucleation in iron based alloys was reconsidered. It is indicated that the critical nucleation work is one order of magnitude lower than the thermal energy,suggesting that martensite in iron based alloys can be nucleated by thermal fluctuation. The early small particle experiments and relevant experimental data were analyzed,revealing that the homogeneous martensitic nucleation mechanism is compatible with the experimental results.
LI Ge-yang, SHI Xiao-rong, WU Liang, XU Jun-hua, RONG Yong-hua, ZHANG Hui-juan. A Study of TiN/AlN Nano Multilayers[J]. Journal of Materials Engineering, 1999, 0(11): 6-9,13.
TiN/AlN nano-multilayers were fabricated by reactive sputtering method. The microstructure and mechanical properties were determined by XRD, HREM and microindentor respectively. The results show that TiN/AlN nano-multilayers have a good periodic modulation structure. AlN layers grow epitaxilly on the TiN layers as FCC structure in nano-multilayer with short modulation wavelength. However, hexagonal crystals appear in AlN layers with modulation wavelength increasing. The microhardness of TiN/AlN nano-multilayers increases with reduction of their modulation wavelength and reaches the maximum value HK3293 at=2nm.
LI Zhi-jun, LI Xue-cheng, BAO Jian-wen, CHEN Xiang-bao. Study on Mechanical Properties of the M40/5228 Composites[J]. Journal of Materials Engineering, 1999, 0(11): 10-13.
The mechanical properties of M40/5228 composites were investigated under the several conditions. The interface of the composites was characterized by SEM. Compared with M40/4211 composites, M40/5228 composites possesses more excellent mechanical properties, M40/5228 composites has excellent hygrothermal property, while the retention of the flexural properties and shear property is higher than other several composites under the conditions of dry and wet at 130℃.
ZHAO Yong-xiang, GAO Qing, CAI Li-xun, GU Fang-yu. Single Impact Effects on the Low Cycle Fatigue Life of a Stainless Steel Pipe Welded Joint[J]. Journal of Materials Engineering, 1999, 0(11): 14-18,21.
An experimental investigation of the single impact effects with high strain rate on the low cycle fatigue life of 1Cr18Ni9Ti stainless steel pipe-welded joint was performed. A group test (7 specimens for each group) was used. The joint was made without eliminating the welding residual stress. Transient peak strain rate of the test was up to 480s-1. All fatigue tests were made at total strain amplitude of 0.00228 under fully reversal loading mode. The results reveal that the effects are related to a coupling action of the welding residual stress and the impact plastic-induced mechanism. The welding residual stress, plus impact stress, tends to increase fatigue damage, and in contrast, the impact plasticity-induced tends to slow fatigue damage and to decrease the scatter of fatigue life. The former checks the later. In addition, taking into account the scatter of fatigue lifes a probabilistic assessment approach of the single impact effects is presented and its availability is verified by the statistical analysis of test results.
WANG Quan-sheng, WANG Jiang-bo, WANG Fu-chi, LÜ Guang-shu. Thermal Shock of Gradient Thermal Barrier Coatings[J]. Journal of Materials Engineering, 1999, 0(11): 19-21.
mm thick gradient TBCs were got by plasma spraying,including NiCrAl-YPSZ and Ni/Al-YPSZ. The test results of thermal shock show that the two kinds of coatings have different failure behavior. The failure of NiCrAl-YPSZ coating is caused by substrate oxidation. The other is from radial cracks penetrating and oxidation.
LI Bang-sheng, JIANG Hai-yan, FAN Hong-bo, LI Qing-chun, YUAN Guang-jiang, MI Guo-fa. High Temperature Mechanical Strength of XD ZL201/TiB2P Composites[J]. Journal of Materials Engineering, 1999, 0(11): 22-23,47.
Submicron in situ TiB2 particulars were precipitated in Ti-Al-B by XD process. The interfacial structures on the atomic scale were studied by HREM. High temperature mechanical properties were measured. Results show that the interface is atomically clear,smooth and free from any interfacial phases At 250℃,the tensile strength, yield strength, and elongation of the composites is up to 300MPa,230MPa,13% respectively.
LIU Yuan-fu, LI Hui-qi, WU Yu-ping. Study on Surface Multicomponent Cementation by Ordinary Pressure Plasma Jet Scanning[J]. Journal of Materials Engineering, 1999, 0(11): 24-28.
Smearing the alloy permeation agent on the inside wall of 45# steel tube in advance,then scanning the surface with high energy plasma jet at ordinary pressure, the multicomponent cementation and quenching were obtained. The composition and microstructure of the harden layer were investigated by electron probe and transmission electron microscopy. The results show that the depths through which B,Si,Ce penetrate are different one another The microstructures of the harden layer are needle-like martensite and boron-silicon compounds. The level of the harden layer's microhardness is high and the gradient of the microhardness is reasonable The wearability of the harden layer is well. The corrosion resistance of the harden layer is improved obviously.
GUO Jing-jie, SU Yan-qing, REN Zhi-jiang, JIA Jun. Nitrogen Solubility and its Control in Ti153 Melt During ISM Process[J]. Journal of Materials Engineering, 1999, 0(11): 29-32.
The influence factors on nitrogen solubility in Ti153 melt were analyzed based on the thermodynamic model set up in this paper. The results show that melt temperature and nitrogen partial pressure in melting chamber have important influence on the nitrogen solubility. Therefore a method to decrease nitrogen solubility is put forth. This method has been using during ISM process and the experimental results are accordance with the calculated results.
SUN Xin-jun, GU Jia-lin, BAI Bing-zhe, CHEN Nan-ping. Fabrication of Submicron Grained Titanium Alloy by Compressive Deformation[J]. Journal of Materials Engineering, 1999, 0(11): 33-35.
The possibility to produce ultrafine grained titanium alloy by compressive deformation was examined tentatively. It is shown that submicron-grained TC11 alloy can be obtained by compressive deformation below 725℃. During microstructure refinement, dynamic recrystallization occurs only in α phases, and β phases undergo a process of precipitation and growth. Compared with the situation of static annealing, deformation can not only enhance the precipitation and growth of β phases but also change the morphology of β precipitates.
ZHANG Yu-min, HAN Jie-cai, HE Xiao-dong, DU Shan-yi. Applications of Rapid Prototyping Technique in the Field of Ceramics[J]. Journal of Materials Engineering, 1999, 0(11): 37-40,44.
Some rapid protoptyping mathods were introduced briefly with emphasis on applications of rapid prototyping technique in the field of ceramics. The problems and prospect of ceramics preparation with the technique were also discussed.
FAN Gui-bin, TAN Ju-fen, LI Si-qing, DENG Ji-xiong, SHEN Biao. Review of Metallurgical Quality for Domestic Aeronautical Materials from Examinating External Materials[J]. Journal of Materials Engineering, 1999, 0(11): 41-44.
The metallurgical quality of external materials was mastered by means of examinating external materials such as superalloys, titanium alloys, stainless steels, welding rod and solder. The superior metallurgical quality of external materials rests with the strict contronl for impurity elements and scatter of alloy elements. The method of improving metallurgical quality of domestic material was proposed.
ZHAO Ai-guo, ZHONG Pei-dao, YAN Hai. Cracks Analysis of Chair Slide in a BJ2021 Jeep[J]. Journal of Materials Engineering, 1999, 0(11): 45-48.
In this paper, the characteristics and the modes of the cracks in chair slide in a BJ2021 jeep were analysed. It is shown that the cracks are characterized by typical fatigue, the bad fixation and the alternative stresses are responsible for the fracture of slide.
