Xudong ZHANG
,
Wuzhu CHEN
,
Cheng WANG
,
Lin ZHAO
,
Yun PENG
,
Zhiling TIAN
材料科学技术（英文）
3 mm thick 400 MPa grade ultrafine grained ferritic steel plates were bead-on-plate welded by CO¬2 laser with heat input of 120~480 J/mm. The microstructures of the weld metal mainly consist of bainite, which form is lower bainite plates or polygonal ferrite containing quantities of dispersed cementite particles, mixed with a few of low carbon martensite laths or ferrite, depending on the heat input. The hardness and the tensile strength of the weld metal are higher than those of the base metal, and monotonously increase as the heat input decreases. No softened zone exists in heat affected zone (HAZ). Compared with the base metal, although the grains of laser weld are much larger, the toughness of the weld metal is higher within a large range of heat input. Furthermore, as the heat input increases, the toughness of the weld metal rises to a maximum value, at which point the percentage of lower bainite is the highest, and then drops.
关键词:
Laser welding
,
null
,
null
,
null
B.C.Samanta
,
T.Maity
材料科学技术（英文）
An investigation was carried out to modify the toughness of triethylene tetramine cured DGEBA (diglycidyl ether of bisphenol-A) resin using solid amine terminated poly (ethylene glycol) benzoate (ATPEGB) as modifier with and without red mud waste particles. The solid ATPEGB modifier synthesized from the acid catalyzed esterification reaction of poly (ethylene glycol) (PEG) and 4-amino benzoic acid was characterized by Fourier transform infrared spectroscopy (FT-IR) and 1H-NMR (nuclear magnetic resonance) spectroscopies, viscosity measurements, and solubility parameter calculation. The unfilled and red mud waste filled modified epoxy networks were evaluated with impact, adhesive, tensile, flexural and thermal properties by differential scanning calorimetry (DSC), thermogravimetric (TG) and dynamic mechanical analysis (DMA). The effect of modifier concentration and red mud waste particles on toughening behavior was also investigated. The optimum properties were obtained at 12.5 phr (parts per hundred parts of resin) concentration of the modifier. The ATPEGB modified cured epoxy was thermally stable up to 315℃. The morphology on fracture surfaces of cured epoxy was also analyzed by scanning electron microscopy (SEM).
关键词:
Epoxy
,
toughness
,
adhesive
,
morphology
董晓明
,
张忠铧
,
尹卫东
,
陈功明
上海金属
采用扫描电镜和透射电镜微观分析手段,对深井用超高强度高韧性套管中Mo合金元素对韧性的影响以及管坯制造工艺对套管韧性的影响进行研究,发现析出相的尺寸和分布以及成分偏析造成的组织不均能够显著影响材料的韧性.通过合金化和微合金化以及成分偏析控制技术研究,开发出具有优异夏比冲击韧性的140 ksi和155 ksi钢级的套管材料,材料在0℃下的夏比横向冲击功超过了屈服强度的10％以上.
关键词:
超高强度
,
高韧性
,
套管
,
深井
,
组织
,
韧性
王钟炜
,
黎雨
,
李伟
,
金学军
上海金属
为了研究不同成分和组织的9Ni钢的性能与组织的相互关系,对三种不同成分的9Ni钢进行了组织的检验和性能的测试.结果发现,9Ni钢的基体组织为铁素体、贝氏体或者回火马氏体,少量奥氏体作为第二相分布在基体中.低温韧性主要取决于基体组织,第二相奥氏体也会影响低温韧性;针状铁素体或者贝氏体基体可提高9Ni钢的低温韧性.
关键词:
9Ni钢
,
不同成分
,
组织
,
韧性
Jianli WANG
,
Myonghoon LEE
,
Kejian YAO
,
Jianbin JI
,
Xiaomei YU
材料科学技术（英文）
Mechanical properties of epoxy resin were investigated by adding core-shell elastic particles (CSEP). The results indicated that optimized core-shell ratio was 60/40 and the loading volume of CSEP was 10 phr (per hundred parts of epoxy resin by weight). The impact strength of modified systems increased apparently with the decrease of core sizes. However, the shearing strength changed gently with the particle sizes. CSEP with lightly crosslinked rubbery core showed more effectiveness on toughness than others. With solution blending, CSEP could be dispersed in epoxy matrix well, and the morphologies of dispersed rubber domains were controlled perfectly by CSEP whose structure was predesigned. A cavitation-shearing band toughness mechanism was observed from the SEM micrographs of fracture surface. It also was found that the deforming temperature (DT) of modified epoxy did not decline apparently.
关键词:
Epoxy resin
,
null
,
null
