Huaping XIONG
,
Lianmeng ZHANG
,
Junguo LI
,
Runzhang YUAN
材料科学技术（英）
The tungsten heavy alloys with Ni-Al and Fe-Al additives were sintered by hot-press method at 1473 K for 1 h. It was found that the relative density of the W-Fe alloy could be increased evidently by addition of Al. However, the relative density of W-Ni-Al alloy with low content of Al was conversely decreased considerably compared with that of W-Ni alloy. The causes have been studied. The sintering experiments of Mo alloy and W-Mo alloys with 3 wt pct Fe-1.5 wt pct Al additives were also carried out under the same sintering condition of low temperature. Finally, W-Mo system FGM with density gradient was successfully fabricated. Its density changed gradually from 17.0´103 kg/m3 to 9.5´103 kg/m3 within the middle 1.1 mm thickness range.
关键词:
Daoren GONG
,
Zhongmin YANG
,
Qiang SHEN
,
Lianmeng ZHANG
材料科学技术（英）
Mo is difficult to sinter densely at a relatively low temperature due to its high melting point. In the present paper, by adding different weight contents of Ni and Cu additives, Mo alloys have been densified at 1473 K for an hour by hot-pressing method, and the optimum contents of Cu and Ni additives have been acquired: when the contents of Ni and Cu are 3 and 2 wt pct respectively, the relative density of the sample reaches the maximum value. It was found that when the Ni-Cu solid solution was added into Mo alloys, the achieved density is higher than the case of Ni and Cu additives. The experimental results indicate that, Ni and Cu play different roles in the process of sintering, the Ni-Cu solid solution has the same function as Ni and Cu additives in the course of sintering Mo alloys, It shows more activating sintering feature for Mo than the Ni and Cu additives.
关键词:
Mo alloys
,
null
,
null
,
null
Hong TAO
,
Chengji DENG
,
Lianmeng ZHANG
,
Runzhang YUAN
材料科学技术（英）
Al/Al2O3 composites of different ratios were hot-press sintered at 575 similar to 640℃ under a pressure of 30 MPa for 2 h in a vacuum furnace. It was found that the relative density of the Al/Al2O3 composites could be increased evidently with the rise of sinter temperature. No reaction occurred between Al and Al2O3 at the sinter temperatures. Under 640℃-30 MPa-2 h experimental condition, Al/Al2O3 system FGM was successfully fabricated, and its density range changed quasi-continuously from 2.887x10(3) kg/m(3) to 3.1909x10(3) kg/m3 within the middle 1.0 mm thickness range.
关键词:
Qiang SHEN
,
Lianmeng ZHANG
,
Lidong CHEN
,
Takashi GOTO
,
Toshio HIRAI
材料科学技术（英）
In contrary to the commonly used arc melting method, samples in the present paper were prepared by the solid state reaction from elemental powders at 1173 K under a flowing Ar atmosphere for 96~168 h. The constituent phases and the elemental compositions were determined and shown that the samples were of single phase and stoichiometry. Then the spark plasma sintering technique was used to consolidate them. It is found that, dense ZrNiSn-based compounds with fine grain size and homogeneous microstructure were achieved under the condition of 1123 K/40 MPa/25 min.
关键词:
ZrNiSn
,
null
,
null
,
null
Zhongmin YANG
,
Lianmeng ZHANG
,
Qiang SHEN
材料科学技术（英）
A sedimentation method is proposed to fabricate functionally graded materials (FGMs) with the continuous and smooth variations of composition. The relations between the compositional distribution of deposited body and the powder characteristics of raw materials as well as settling parameters are derived. Subsequently, the mathematical model of forming FGM based on the co-sedimentation has been established. At last, numerical simulations are conducted to explore the effects of the particle sizes of raw materials and suspension height on the compositional distribution of final products.
关键词:
Calculation
,
null
,
null
Chuanbin WANG
,
Qiang SHEN
,
Lianmeng ZHANG
材料科学技术（英）
In this study, Cu was added as the third additive to lower the sintering temperature of W-Ni-Fe alloy. By adding 2 wt pct Cu, a dense 93W-3.5Ni-1.5Fe-2.0Cu tungsten alloy was obtained by hot-pressing at a low temperature of 1573 K which is a process of liquid-phase sintering. As a result, the morphology of W-Ni-Fe alloy changed obviously after the addition of Cu and the alloy had higher relative density and rupture strength. The mechanism of the densification of W-Ni-Fe-Cu alloy at the low temperature was then mainly investigated. It was found that, part sintering activators Ni and Fe could exist in liquid form at 1573 K due to the addition of Cu, which made it easy for Ni and Fe to dissolve W and thus the full densification of W-Ni-Fe-Cu alloy at the low temperature was realized.
关键词:
W-Ni-Fe alloy
,
null
,
null
