Jitai NIU
,
Wei GUO
,
Qingchang MENG
,
Xinmei ZHANG
,
Xingqiu LIU
,
Guangtao ZHOU
材料科学技术（英）
The liquid-phase-impacting (LPI) diffusion welding mechanism and microstructure of welded joint of aluminum matrix composite SiCp/101A have been studied. It shows that by LPI diffusion welding, the interface state between SiC particle and matrix is prominent, the harmful microstructure or brittle phase can be restrained from the welded joint. Moreover, the density of dislocation in the matrix near the interface and in the matrix are all so higher than that of parent composite, the dislocation entwists each other intensively resulted in welding the composite successfully.
关键词:
Aluminum matrix composite
,
null
,
null
Wei GUO
,
Qingchang MENG
,
Jitai NIU
,
Xinmei ZHANG
材料科学技术（英）
In this paper, a new method for welding SiCp/101A was put forward. It is LPI (liquid-phase-impacting) diffusion welding. Through LPI diffusion welding SiCp/101A aluminum, the effect of welding parameters on the welded joint property was investigated, and the optimal welding parameters were brought forward at the same time. The microstructure of joint was analyzed by means of optical-microscope, scanning electron microscope in order to study the relationship between the macro-properties of joint and the microstructure. The results show that LPI diffusion welding could be used for welding aluminum matrix composites SiCp/101A successfully.
关键词:
Aluminum matrix composite
,
null
,
null
Congqin NING
,
Qingchang MENG
,
Yu ZHOU
,
Haitao LIU
材料科学技术（英）
Composite coatings of bioglass and hydroxyapatite (briefly named HA/BG) with different hydroxyapatite contents on titanium substrate were successfully fabricated. The fabricated coatings are characterized by rough and poriform surface.The densities of the coatings decrease with the increase of HA content. There is a transition layer with a 5 μm thickness between the BG coating and the substrate. During heat-treatment, hydroxyapatite crystals with hexastyle shape have precipitated from the BG.
关键词:
Mufu YAN
,
Qingchang MENG
,
Jihong YAN
材料科学技术（英）
Two materials, pure Fe and pure Al, were nitrided in a pulse plasma nitriding facility. The nitrogen profiles in surface layers and the surface phase structures of specimens nitrided at 500℃ for 8 h for Fe and for 6 h for Al were measured using the glow discharge spectrometry and an X-ray diffractometer, respectively. XRD results indicate that the compound layer with hcp crystal structure (AlN) was formed on the top of Al substrate. During nitriding of Fe, the compound layer growth conforms to parabolic law and the surface nitrogen concentration change little with increasing the nitriding time. The surface nitrogen content of nitrided Al specimens is less than theoretical value 34.17 wt pct of AlN. The mathematical models of nitrogen concentration profiles in the surface layer of nitrided Al specimen have been established based on the research of the kinetics of pulse plasma nitriding of Fe and the nitrogen concentration profiles were also simulated. Results show that the predicted curves agree basically with the experimental data.
关键词:
Pulse plasma nitriding
,
null
,
null
