Xinbin HU
,
Mei ZHANG
,
Xiaochun WU
,
Lin LI
材料科学技术（英）
Based on the local equilibrium assumption, coarsening behavior of M23C6 carbide at 700℃ in H13 steel was simulated by DICTRA software. The results from the calculations were compared with transmission electron microscopy (TEM) observations. The results show the interfacial energy for M23C6 in H13 steel at 700℃ is thus probably 0.7 J•m-2, which fits the experiments well. The influence of composition and temperature on the coarsening rate was also investigated by simulations. Simulations show a decrease in the coarsening rate when V/Mo ratio is increased, while the coarsening rate increases with increasing temperature.
关键词:
DICTRA Simulation
,
碳化物粗化
,
界面能
,
H13钢
Yanlin HE
,
Lin LI
,
Xiaochun WU
,
Patrick WOLLANTS
材料科学技术（英）
The improvement of machining behavior of prehardened-mould steel for plastic is realized by using computer-aided composition design in this work. The results showed that the matrix composition of large sectional prehardened mould steel for plastic markedly influences the precipitation of non-metallic inclusion and the control of composition aided by Thermo-Calc software package minimizes the amount of detrimental oxide inclusion. In addition the modification of calcium is optimized in the light of composition design.
关键词:
Prehardened-mould steel for plastic
,
null
,
null
,
null
Lingyun XU
,
Xiaochun WU
,
Hongbin WANG
材料科学技术（英）
In order to lower the boriding temperature of hot work steel H13, method of surface mechanical attrition treatment (SMAT), which can make the grain size of the surface reach nano-scale, was used before pack boriding. The growth of the boride layer was studied in a function of boriding temperature and time. By TEM (transmission electron microscopy), SEM (scanning electron microscopy), XRD (x-ray diffraction) and microhardness tests, the grain size, thermal stability of the nano-structured (NS) surface and the thickness, appearance, phases of the surface boride layer were studied. Kinetic of boriding was compared between untreated samples and treated samples. Results showed that after SMAT, the boride layer was thicker and the hardness gradient was smoother. Furthermore, after boriding at a low temperature of 700℃ for 8 h, a boride layer of about 5 μm formed on the NS surface. This layer was toothlike and wedged into the substrate, which made the surface layer combine well with the substrate. The phase of the boride layer was Fe2B. Research on boriding kinetics indicated that the activation energy was decreased for the treated samples.
关键词:
Boriding
,
表面机械研磨处理
,
H13钢
,
渗硼动力学
