KANG Jin xing, ZHAO Wen-zhen. Effect of WC on Cavitation Erosion Resistance of Copper-based and Nickel-based Coatings[J]. Journal of Materials Engineering, 2002, 0(3): 3-6.
WC particle was added in CuNiSiB and NiCrSiB self-fluxing alloy powder.The coating were made with flame spray welding.The cavitation erosion were investigated by ultrasonic vibration cavitation instrument.The cavitation erosion morphology was observed by SEM. Results show that the cavitation erosion resistance of composite coating is better than based alloy.That raising the cavitation erosion resistance of CuNiSiB coating method is to reinforce grain boundary.Cavitation erosion mechanisms of the test coatings was also discussed in the paper.
ZHOU Jian, GUO Jian-ting, LI Gu-song. Effect ofAg Alloying on Microstructure and Properties of NiAl Inter metallic Compound[J]. Journal of Materials Engineering, 2002, 0(3): 7-9,13.
In this paper,the effects of Ag on microstructures and compressive properties of NiAl intermetallic compound were investigated. The present results show that the NiAl Ag alloys are consisted of two phases:β-NiAl and Ag-rich solid solution. The amount of the second Ag-rich phase increases with increasing. Ag-content Ag has very low solubility inNiAl and they form pseudo binary monotectic systems. The addition of 0.5-1(atom fraction/%)Ag to NiAl increased its strength while the addition of more than 1(atom fraction/%)Ag decreased its strength. The strengthening and weakening effects come from solid solution hardening and second ductile phase softening In addition,Ag alloying can improve the room temperature compressive ductility of NiAl.
PENG Zhi-fang, WANG Yan-qing, REN Yao-yao, LIU Yan, SHI Yu-xiang. Phase Amount Distribution and its Effects on High Temperature Tensile Properties of a Ni-Cr-Co Superalloy[J]. Journal of Materials Engineering, 2002, 0(3): 10-13.
The Characteristics of phase amount distribution and their effects on high temperature tensile properties were determined on the samples of a NiCrCo base superalloy treated by solid solution of 1150℃/17h,and then followed by aunstress-ageing treatment(8,100,500 and 1000h) and a stress aging treatment(100,500 and 1000h),respectively. With the increase of aging time,the following results were obtained. The carbide amount at grain boundaries was decreased for the stress aged samples and increased for the unstress aged samples,respectively. The carbide amount at grain boundaries and in the grain interiors exhibited an opposite varying tendency. The amount of γ′phase in the grain interiors was increased when samples were aged for a shorter period of time,and then decreased. The 780℃ tensile strength was decreased with the increase of the carbide amount at grain boundaries for the unstress aged samples and the opposite was true for the stress aged samples. The analysis and discussions were made for the above results in the paper.
LI Bo, XIA Dong-sheng, GUO Jian-ting, Li Gu-song. Synthesis Mechanical Property of NiAl(Co)-TiC Nano-Composite[J]. Journal of Materials Engineering, 2002, 0(3): 14-16.
Ni,Al,Co,Ti and C was mixed with Ni50Al45Co5+10% TiC and Ni50Al45Co5+20% TiC ratio and processed with mechanical alloying in high energy balling. After the nano composite powder was treated by hot pressing(HP) and hot isostatically pressing(HIP),sthe bulk nano composite with the gain from 100～350nm and embedded TiC nano paritcles from 80～250nm was obtained At room temperature,the yield strength and compressibility was 1394～1660MPa and 12%～13%,respectively.The surface of NiAl(Co)-20TiC nano composite with 30% compressibility was smooth without crack in 700℃ In 1100℃,the yield strength of bulk nano-material was 136MPa,which was 4 times than that of the cast NiAl.
XIONG Hua-ping, LI Xiao-hong, MAO Wei, MA Wen-li, CHENG Yao-yong. Study on Surface Modification of TiAl-based Alloy by Al-Si Alloy[J]. Journal of Materials Engineering, 2002, 0(3): 17-19.
Siniconizing treatment on surface of TiAl-based alloy was conducted by Al-Si molten alloy within the temperature range from 913K to 1053K.Due to the surface modification,interfacial reactions occured between the TiAl based alloy and the Al-Si molten alloy,resulted in the formation of gray martrix and black phases of tiny block or strip composed of elements of Si,Ti and Al-It was found that,after oxidation at 1173K for 100 hours,thin oxide film of Al2O3、SiO2,as well as the stable Si-Ti-Al phases were formed on the surface of siniconized TiAl-based alloy. There,oxidation resistance of the TiAl-based alloy was greatly improved.
GUI Zhong-lou, WU Chang-xin, SUN Chuan-qi, LI Qi-juan, DAI Xiu-yan. Research on Manufacture Technology of Superalloy Ingots with Premium Quality[J]. Journal of Materials Engineering, 2002, 0(3): 20-23.
Manufacture technology of aerospace superalloy ingots with premium quality(BIAM Technology)have been researched,which significantly lowers the gas and detrimental elements content,improves ingot surface quality,and simultane ously improves the creep property of superalloy. The level of the gas and detrimental elements content and surface quality of the superalloy ingots manufactured by BIAM Technology have reached the premium quality grade of similar superalloy ingots abroad.
ZHENG Qi, HOU Gui-chen, SUN Xiao-feng, JIN Tao, GUAN Heng-rong, HU Zhuang-qi. Effect of Sample Size on Solidified SC Structure[J]. Journal of Materials Engineering, 2002, 0(3): 24-27.
The effects of sample size on solidified SC structure were studied.The results show that,the thinner the sample,the finer the structure,specially for the primary dendrite spacing and the size of γ′phase;the real size effect is the ratio of surface area to volume of the sample(A/V)on the temperature gradient and solidified structure and rupture life; primary dendrite spacing and size of interdendritic γ′phase is a linear function of A/V ratio;the temperature gradient and the rupture life are changed markedly by the variation of sample size.
YAN Xiao-feng, MA Hui-ping, LU Ya-xuan, LIU Wan-sheng. Effect of Chromium Content on Microstructure and Mechanical Properties of GH648 Alloy[J]. Journal of Materials Engineering, 2002, 0(3): 28-31.
GH648 is an aging-strengthening Ni-based superalloy,which is mainly applied as a mechanical part in the aviation motor and works below 900℃. There exist several secondary phases such as α Cr、γ′and carbides in this alloy.Chromium plays a very important role in the form of the precipitates mentioned above,and the effect of Cr content on microstructure and mechanical properties of GH648 alloy is studied in this paper by means of light and electron microscope and physical-chemical analysis.Experimental results show: when Cr content increases,α Cr and γ′precipitates and primary carbides increases,and the alloy characterizes with good combination of mechanical properties when Cr content ranges from 320% to 330%.
CHEN Huan-ming, HU Ben-fu, YU Quan-mao, SONG Duo. A Study of Dendrite Microsegregations on PREP FGH95 Powders[J]. Journal of Materials Engineering, 2002, 0(3): 32-35.
The dendrite microsegregations in PREP FGH95 powders hasbeen studied by using SEM.The results show that there are riched with Mo,Ti,Nielements,and poored with Ni,Co,Wele-ments between the powders dendrite rm.Italsoseems that the dendr itemicrosegreg ations decrease
with decreasing part icle size.Compared with argon-atomized powders,the dendr item icrosegre-gations in PREP FGH95 powdersis lower.
JIN Tao, LI Jin-guo, ZHAO Nai-ren, WANG Zhen, SUN Xiao-feng, GUAN Heng-rong, HU Zhuang-qi. Effects of Withdrawal Rate on Solidification Parameters and Microstructure of a Nickel-base Single Crystal Superalloy[J]. Journal of Materials Engineering, 2002, 0(3): 36-39,48.
Effects of withdrawal rate on solidification parameters and microstructure of a nickel base single crystal superalloy were investigated. The results show that,with the decrease of the withdrawal rate,the temperature gradient in solid liquid interface is increased obviously and the width of mushy zone was reduced.The temperature gradient is stable when the withdrawal rate is very low.With the increase of the withdrawal rate,the morphology of liquid solid interface transforms from cellular to dendritic,the size of the γ′precipitates decreases,the shape of γ′precipitates tend to regular,the amount of γ/γ′eutectic increases and the size of primary γ′precipitates in γ/γ′eutectic decreases.
HUANG Wei-dong, LI Yan-min, FENG Li-ping, CHEN Jing, YANG Hai-ou, LIN Xin. Laser Solid Forming of Metal Powder Materials[J]. Journal of Materials Engineering, 2002, 0(3): 40-43,27.
The fundamental principle,development state,solidification microstructure and forming characters of laser solid forming(LSF) were investigated throughly.It was found that to acquire idea forming result,the height,width and the overlap rate of the single cladding layer must be accurately controlled.The forming principle of the microstructure was also studied during laser solid forming in this paper.The microstructure of the sample was made up of thin and long epitaxial growth dendrites,the primary spacing of which is about 10~30μm. The directional solidification microstructure or even single crystal was obtained based on the rigid processing characters control.Combining the research results of the forming character,the samples with different metal were obtained by using optimized processing characters.The inner part of the sample wa dense,the surface quality was fine and was free of defect.
GUO Wei-min, FENG Di, WU Jian-tao, ZHANG Feng-ge, ZHANG Ying, ZHANG Yi-wen. Research and Development of P/M Superalloy Metallurgic Techniques[J]. Journal of Materials Engineering, 2002, 0(3): 44-48.
Research achievement on powder producing,powder treating,forming process heat treatment of Ni-base superalloy is presented and analyzed,and problems is also discussed.The major tendency of P/M superalloy metallurgic technics is indicated.
