叶威
物理测试
本文通过研究热处理工艺对金属TiC陶瓷刀具基体3Cr13组织的影响，提出了改善组织韧性的热处理工艺。该工艺下，基体原马氏体组织中沿晶界呈网状分布有脆性碳化物被消除，获得了晶粒细小的全马氏体组织，从而极大地提高了刀具基体的韧性，有效地提高了刀具抗断裂的能力，降低了断刀率。
关键词:
TiC
,
Cutter
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Fracture
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Heat treatment
Ruijing ZHANG
,
Ke YANG
,
Tianying XIONG
材料科学技术（英）
Nano-SiO2 with high activity and mesopores was prepared through sol-gel synthesis followed by low-temperature heat treatment and ball milling firstly in our experiments. TEM was performed to measure particle sizes. Nitrogen adsorption experiments were carried out to estimate specific surface area, porous distribution and porous ratio by BET and BJH methods. The content of Si-OH in SiO2 surface was calculated by analysis of the results of hydrogen-oxygen content mensuration (HOCM). As a result, appropriate heat treatment system and ball milling time are important to preparation for nano-SiO2 with high activity and mesopores, which are 5~50 nm particles, 5~6 nm average aperture, 85%~93% porous ratio, and 51%~55% Si-OH content in surface. Nano-SiO2 with that structure has high surface energy and activity. This process, which has simple facilities and operation rules, is a new way of preparation for nano-SiO2 with high activity and mesopores.
关键词:
Heat treatment
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null
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null
,
null
Pingli MAO
,
Yan XIN
,
Ke HAN
,
Weiguo JIANG
金属学报(英文版)
doi:10.1016/S1006-7191(08)60110-6
The volume fraction and morphology of the TCP-phase formed in two kinds of Ni-Mo-Cr-Re superalloys under different heat treatment conditions were investigated in this paper. In Re-5% alloy, with increasing of the heat treatment temperature and prolonging the holding time, the volume fraction of TCP-phase decreased and the TCP-phase size increased. At relatively lower temperature, the TCP-phase prefers to present in the dendrite cores. In Re-10% alloy, the volume fraction and size have the same change tendency as that of in Re-5% alloy, but the morphology will change from needle-like and block-like to sphere when the temperature increases. The TCP-phases formed in these two Ni-Mo-Cr-Re alloys are σ and P phase.
关键词:
Heat treatment
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null
,
null
Lugui CHEN
,
Yong LING
,
Xiuhong KANG
,
Lijun XIA
,
Dianzhong LI
材料科学技术（英）
A large-scale, thin wall duplex stainless steel impeller with complex geometry was deformed severely and unpredictably during casting and heat treatment processes resulted in dimensional failure for the final part. In this paper, the distortion of the impeller during casting and heat treatment was calculated. A commercial software, Experto-ViewCast, was used to simulate the transient heat transfer, solidification and mechanical behaviors during the casting and the heat treatment process. The coupled set of governing differential equations for mass, energy and mechanical balance were solved by finite control volume and finite element method. A thermoelastic-visco-plastic rheological model was used to compute the constrained shrinkage of the casting. At each time increment, a coupling of the heat transfer and mechanics was performed. Comparison of the experimental measurements with the model predictions showed good agreement. From the calculated displacements of key points of the blade, the proper inverse displacements were determined to provide an optimum casting pattern and to achieve a uniform and reasonable machining allowance for both faces of the blade.
关键词:
Numerical simulation
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null
,
null
,
null
,
null
Wei HAN
金属学报(英文版)
304 stainless steel coating was deposited on the Interstitial-Free steel substrate by cold gas dynamic spraying (CGDS). Three-point bending test of the cold sprayed 304 stainless steel coating was tested by SHIMADZU electro-hydraulic servo-controlled fatigue testing machine and the fracture morphology was examined by scanning electron microscopy. The results showed that the fracture behavior of the cold sprayed 304 stainless steel coating was brittleness fracture. The crack in the coating occurred in the interfaces between particles and the crack extended to the internal of the coating with the increase of the load. When the crack has extended to the combination interface between coating and substrate, the crack extended to the two sides. The microstructure and mechanical property of the cold sprayed 304 stainless steel coating have been optimized after heat treatment.
关键词:
Cold gas dynamic spraying
Zhirong HE
,
Fang WANG
,
Jing'en ZHOU
材料科学技术（英）
The basic martensitic transformation (MT) properties of Ru50Ta50 alloy, i.e. MT temperature (MTT), temperature hysteresis (ΔT), and MT heat (ΔH) were investigated in this paper. The effects of heat treatment and thermal cycling on MT behavior of Ru50Ta50 alloy, the deformation and microstructure characteristics of Ru50Ta50 alloy were also studied for its engineering application as high temperature actuator/sensor materials by means of differential scanning calorimetry, X-ray diffraction, transmission electron microscope, optical microscope, and hardness test. The results showed that a two-stage reversible MT takes place in Ru50Ta50 alloy. The two-stage MT starting temperatures (MS1 , MS2 ) and the temperature hysteresis (ΔT1, ΔT2) are 1047, 784 and 11, 14℃, respectively. No significant effect of aging treatment and thermal cycling on MTT and ΔT of Ru50Ta50 alloy were observed, but ΔH decreases slowly with increasing thermal cycles. The hardness and brittleness of Ru50Ta50 alloy are high. The deformation mode of RuTa alloys is twinning.
关键词:
RuTa alloy
,
热处理
,
热循环
,
形状记忆合金
,
Ru
A.Wiengmoon
,
T.Chairuangsri
,
N.Chomsang
,
N.Poolthong
,
J.T.H.Pearce
材料科学技术（英）
Effects of heat treatments on hardness and dry wear properties of a semi-solid processed Fe-26.96 wt pct Cr-2.91 wt pct C cast iron were studied. Heat treatments included tempering at 500℃, destabilisation at 1075℃ and destabilisation at 1075℃ plus tempering at 500℃, all followed by air cooling. Electron microscopy revealed that, in the as-cast condition, the primary proeutectic austenite was round in shape while the eutectic M7C3 carbide was found as radiating clusters mixed with directional clusters. Tempering did not change the microstructure significantly when observed by scanning or transmission electron microscopy. Destabilisation followed by air cooling led to a precipitation of secondary M23C6 carbide and a transformation of the primary austenite to martensite. Precipitation behaviour is comparable to that observed in the conventionally cast iron. Tempering after destabilisation resulted in a higher amount of secondary carbide precipitation within the tempered martensite in the eutectic structure. Vickers macrohardness and microhardness in the proeutectic zones were measured. Dry wear properties were tested by using a pin-on-disc method. The maximum hardness and the lowest dry wear rate were obtained from the destabilisation-plus-tempering heat treatment due to the precipitation of secondary carbides within the martensite matrix and a possible reduction in the retained austenite.
关键词:
Semi-solid process
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null
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null
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null
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null
王医锋
,
何晓聪
,
曾凯
,
刘福龙
宇航材料工艺
doi:10.3969/j.issn.1007-2330.2015.05.013
通过搭建局部热处理试验装置,对镀锌钢压印接头部位进行火焰淬火处理.然后对试件进行力学性能测试,制备金相试样观察分析经过局部热处理后接头显微组织,并对比热处理前后组织的显微硬度.结果表明:火焰淬火使接头失效时颈部撕裂程度变大;拉剪强度提高16.7%;经过火焰淬火处理接头部位材料组织呈现为板条状马氏体,该组织较未经过热处理的组织显微硬度提升了12.1％.
关键词:
压印接头
,
热处理
,
拉剪强度
,
显微组织分析
江行国
,
程晓华
,
文华
,
柳永宁
新型炭材料
以固体废弃物兰炭焦末为原料,通过硼( B)掺杂及高温处理制备出改性兰炭粉末材料。研究B掺杂量对其作为锂离子电池负极材料的影响。结果表明,B掺杂质量分数为8%时,经2300益高温处理,兰炭的电化学性能达到最佳,首次脱锂容量为361 mAh/g,在1 C电流密度下经300次循环后,容量为314 mAh/g,表现出较为优良的循环性能。
关键词:
锂离子电池负极材料
,
石墨
,
兰炭
,
掺杂
,
热处理
