Changzhong WU
,
Huaining CHEN
,
Jing CHEN
,
Quanhong LIN
材料科学技术（英文）
The explosion treatment technique has been used in the relief of residual stresses in 800 MPa grade high strength steel manual welded joints. The residual stresses on surface and through thickness of the weldment were measured for both as-welded and explosion-treated sample, the mechanical properties of welded joints under different conditions were also tested. The effect of explosion treatment on the fracture toughness of materials with a residual defect was investigated by crack opening displacement (COD) test. The results show that explosion treatment can reduce not only the surface residual stress but also the residual stress through thickness in the welded joints. The effect of explosion treatment on the mechanical properties and a residual defect in welded joint were inconspicuous.
关键词:
High strength steel
,
爆炸处理
,
残余应力
,
接头力学性能
,
CO
Xiaonan GUO
,
Xin LONG
,
Huaining CHEN
,
Liangshan CHEN
,
Guangjun GAI
材料科学技术（英文）
A softening zone with recrystallized grain around the prepared crack tip in the shock waves treated C-Mn steel weld metal was observed. It is suggested that a dynamic recovery occurred around the prepared crack tip even at a low explosion pressure (5 GPa) because of the stress and strain concentration at the crack tip when shock waves pass through. This result supports the previous work on the improved mechanical properties of a shock treated welded joint with residual crack from the viewpoint of microstructure.
关键词:
Shulan ZHANG
,
Huaining CHEN
,
Quanhong LIN
材料科学技术（英文）
In this paper the preparation technique of surface nanocrystallization in commercial pure titanium was carried out by surface mechanical attrition treatment (SMAT). The mean grain size was calculated by using X-ray diffraction (XRD) and transmission electron microscope (TEM), and the results showed that the mean grain size of the surface was refined to nm level after SMAT treatment. Nanocrystallized surface layers were formed after treated for 5, 15, 30 and 60 min. Microhardness experimental results implied the microhardness obviously increased on the surface layer and it also showed the variation of microhardness at the cross section. Corrosion test results showed the corrosion resistance of the surfaces in the original commercial pure titanium treated by SMAT was not improved in HCl solution. The corrosion micrographs were observed by scanning electron microscope (SEM).
关键词:
Surface nanocrystallization
,
null
,
null
