GUO Zhongcheng
,
LIU Hongkang
,
WANG Zhiyin
,
WANG Min(Department of Metallurgy
,
Kunming institute of Technology
,
Kunming 650093
,
China) Manuscript received 8 May 1995
金属学报(英文版)
The Effects of heat treatment temperature on the hardness,wear resistance and structure of the amorphous Ni-W-P-SiC composite coatings have been investigated.The results show that Ni-W-P-SiC composite coatings are amorphous under 300℃, partially crystalline at 300-400℃,and crystalline when heat treatment temperature reaches 400℃,the crystals being fine Ni3P phase particles.The hardness,wear resistance and the crystallization temperature of the composite coatings increase when an additive is added into the bath.The hardness and wear resistance of the coatings increase with increasing heat treatment temperature,and they will reach their peak values when the heat treatment temperature reaches 400℃.Corrosion experiment indicates that the corrosion resistance of amorphous Ni-W-P-SiC composite coatings in various kinds of corrosive media except nitric acid is better than that of stainless steel 1Cr18Ni9Ti.Scanning electron microscopy observation shows that the additive has no effect on the surface appearance of the coatings,but the current density and the pH value have considerable effects on the surface appearance.
关键词:
:electrodeposition
,
null
,
null
LIU Chunpeng XU Yousheng HUA Yixin Kunming Institute of Technology
,
Kunming
,
650093
,
China.
材料科学技术（英文）
In applying the microwave radiation to extractive me- tallurgy,it is essential first of all to find the extent of microwave energy absorbed by various minerals experi- mentally.In this paper,more than 25 kinds of common useful minerals have been individually irradiated by a 500 W,2450 MHz microwave source in an enclosed quartz crucible to ascertain their heating temperature in a definite time.In addition,the reduction and cbloridization tests were also carried out on the titanomagnetite concentrate and pentlandite with microwave heating,respectively. These experiments indicate potential applications of util- izing microwave energy in extractive metallurgy.
关键词:
microwave radiation
,
null
,
null
,
null
Z. T. Ma and D. Janke(Institute of Iron and Steel Technology
,
Freiberg University of Mining and Technology
,
Germany)
金属学报(英文版)
Useder certain conditions, nonmctallic inclusions such as oxides, sulfides, nitrides and carbides are no longer harmful to sted service properties. With the new concept of oxide metallurgy, these properties can be improved by generating fine oxide inclusions which serve as heterogeneous nuclei for sulfide and fine ferrite[1-4]. A novel continuous casting (CC) process is expected to be created with the utilization of oxide metallurgy. This is also useful for the forthcoming technologies of direct rolling and near-net-shape casting. The main idea of oxide metallurgy consists of an alternative oxidation technology. It is based on steels treated by complex metals such as Ti, Zr, Ti-Zr alloys and rare earth metals. The selected deoxidants should follow the required conditions which are concluded in this paper.
关键词:
oxide
,
null
,
null
,
null
S Narayan
,
A Rajeshkannan
钢铁研究学报(英文版)
An experimental investigation on the workability behaviour of sintered Fe-035C steel preforms under cold upsetting, have been studied in order to understand the influence of aspect ratio and lubrication condition on the workability process. The above mentioned powder metallurgy sintered preform with constant initial theoretical density of 84% of different aspect ratios, namely, 04 and 06 respectively were prepared using a suitable die-set assembly on a 1 MN capacity hydraulic press and sintered for 90 min at 1200 ℃. Each sintered preform was cold upset under nil/no and graphite frictional constraint, respectively. Under the condition of triaxial stress densification state, axial stress, hoop stress, hydrostatic stress, effective stress and formability stress index against axial strain relationship was established and presented in this work. Further more, attained density was considered to establish formability stress index and various stress ratio parameters behaviour.
关键词:
powder metallurgy
,
failure analysis
,
plastic behaviour
,
workability
Q.S. Liu1
,
2
,
3)
,
L.C. Zhao3)
,
G.X. Dong2) and N.J. Gu1) 1) Heibei University of Technology
,
Tianjin 300130
,
China 2) Tianjin Institute of Technology
,
Tianjin 300191
,
China 3) Harbin University of Technology
,
Harbin 150001
,
China
金属学报(英文版)
Theconstruction changinginthereversetransformation ofthestress induced εMin Fe 17 Mn 10 Cr 5 Si 4 Ni alloy is carefully inspected in transmission electron microscope, and then stress induced εM procedure of reverse transformation is analyzed. The behavior of reverse transformationisdissimilar when the organization of εMis different. The reversetransfor mation ofεM withtheshapeofsingle plateandstripisrelativelyeasy,anditsreversibilityincrystallographiciseasilytocarryout,fortheεM with multilayerstructure,thereversetrans formationtakes placein isolatedlayers, fortheεMthat grows well,thereversetransforma tion isrelatively difficult becauseofthe ductile harmonization between itsinternalorganiza tion structures.
关键词:
stress induced εM
,
null
,
null
Yong LIU
,
Lifang CHEN
,
Weifeng WEI
,
Huiping TANG
,
Bin LIU
材料科学技术（英文）
Ti-4.5Al-6.0Mo-1.5Fe, Ti-6Al-1Mo-1Fe and Ti-6Al-4V alloys were prepared by blended elemental powder metallurgy (PM) process, and the effects of Nd on the microstructures and mechanical properties were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). It was found out that the addition of Nd increased the density of sintered titanium alloys slightly by a maximum increment of 1% because small amount of liquid phase occurred during sintering. The addition of Nd shows little effect on the improvement of tensile strength, while the elongation is significantly improved. For example, the elongation of Ti-4.5Al-6.0Mo-1.5Fe can be increased from 1% without addition of Nd to 13% at a Nd content of 1.2 wt pct.
关键词:
Powder metallurgy titanium alloy
,
null
,
null
,
null
A.A.A. Saleh
,
Y. Fu
,
X.J. Zhai
金属学报(英文版)
Nano-ZnO particle was produced by evaporating zinc powders in air at air °ow-rate
from 0.2 to 0.6m3/h. Nano-ZnO particles was formed by the oxidation of the evapo-
rated zinc vapor. X-ray di®raction shows the powders to be ZnO with lattice parame-
ters of a=0.3249nm and c=0.5205nm. The particle size is dependent upon the transit
time from the source to the collection area. The size of particles was ranged between
81 to 103nm. The average density resulted was 4.865g/cm3.
Normal ZnO and nano-ZnO were investigated to use them in aluminum metallurgy as
an inert anode material. A certain amount of both oxides were molded subsequently
inserted to the molten cryolite-aluminum oxide to investigate the corrosive behavior
of both oxides. When the sintering temperature increased up to 1300±C, the weight
loss ratio rose to 5.01%{7.33% and up to 7.67%{10.18% for nano-ZnO and normal
ZnO, respectively. However, when the samples in the molten cryolite aluminum oxide
were put for long time, the corrosive rate was found to be higher. It was found that
the corrosive loss weight ratio of nano-ZnO anode was much lower than the normal
one made from ordinary-ZnO providing that the nano-ZnO is more possible to be use
inert anode material.
关键词:
reactive evaporation method
,
null
,
null
