Changzhong WU
,
Huaining CHEN
,
Jing CHEN
,
Quanhong LIN
材料科学技术（英）
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
Mingfen WEN
,
Bo YU
,
Qiuping WANG
,
Chongli SONG
,
Jing CHEN
材料科学技术（英）
Different nanometer CeO2-ZrO2 mixed oxides doped with lanthanum or ~praseodymium were prepared by coprecipi-tation. The characteristics of all mixed oxides were tested by XRD, SEM, TEM, and XPS. XRD results showed that all oxides were formed solid solution with CaF2 structure at low temperature and had good thermal stability. More Ce4+ ions were rich on the surface by XPS, which were beneficial to oxygen storage. The particle mediun sizes (d50) of all oxides powders were approximately 10~20 nm by small angle scattering goniometer. When doped Zr4+ in CeO2, the specific surface areas were improved at low or high temperature. The area of Ce0.6Zr0.3La0.04Pr0.06O2 powder had excess 110 m2/g after calcining at 923 K for 4h, even calcined at 1273 K for 4 h, the area was up to 65 m2/g.
关键词:
Ceria-zirconia
,
null
,
null
,
null
