ZHOU Bin
,
SHEN Yu
,
CHEN Jun
,
CUI Zhenshan
钢铁研究学报(英文版)
The evolution of eutectic carbide in as-cast M2 high-speed steel on different deforming conditions was investigated. Initially, specimens were deformed by hot compression in the range of 1223 to 1398K at strain rates of 0.01 to 1.0s-1. In a series of continuous deformation tests the flow stress curves were determined for the downstream process simulation. Subsequently, metallographic examination was carried out before and after deformed specimens for carbides analysis. As-cast microstructure is characterized as a spherical matrix of austenite and a continuous network of rodlike or irregular eutectic carbide, whereas deformed microstructure has broken carbide network and smaller granular products on all experimental conditions. It suggests that eutectic carbides fracture to particles during hot deformation by thermomechanical disintegration, while diffusion-controlled phase transformation was not remarkable. Combination with numerical simulation, the relationship between breakdown ratio of carbide network and deforming parameters were concluded. Strain was the most important one to shatter eutectic carbides and disperse products. Furthermore, critical strain values were obtained, beyond which carbide network disappeared, and fractured carbides kept a stable profile and deformed with matrix coordinately. A higher temperature or lower strain rate resulted in a lower critical strain.
关键词:
hot compression;high-speed steel;eutectic carbide;breakdown mechanism
中国腐蚀与防护学报
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关键词:
王浩
,
刘国权
,
秦湘阁
金属学报
采用Potts模型Monte Carlo方法对3种现存的三维个体晶粒长大速率拓扑依赖性
方程进行了仿真验证. 结果表明, Rivier速率方程认为晶粒
体积变化率dVf/dt与晶粒面数f成线性关系, 与仿真
结果明显不符, 不适用于描述三维晶粒长大过程的动力
学. 当晶粒面数f≥8时, Yu-Liu速率方程和
MacPherson-Srolovitz速率方程均与仿真结果很好吻合,
表明这两者均可以用来定量描述三维晶粒长大过程的动力学;当
f<8时, 这两个方程均与仿真结果有显著差异.
关键词:
三维晶粒长大
,
topology-dependent grain growth rate equation
王浩
,
刘国权
,
秦湘阁
金属学报
doi:10.3321/j.issn:0412-1961.2008.01.003
采用Potts模型Monte Carlo方法对3种现存的三维个体晶粒长大速率拓扑依赖性方程进行了仿真验证.结果表明,Rivier速率方程认为晶粒体积变化率dVf/dt与晶粒面数,成线性关系,与仿真结果明显不符,不适用于描述三维晶粒长大过程的动力学.当晶粒面数f≥8时,Yu-Liu速率方程和MacPherson-Srolovitz速率方程均与仿真结果很好吻合,表明这两者均可以用来定量描述三维晶粒长大过程的动力学;当f<8时,这两个方程均与仿真结果有显著差异.
关键词:
三维晶粒长大,拓扑依赖性长大速率方程,Potts模型,Monte Carlo仿真
李文琳
,
李章炜
,
幸七四
,
张扬
贵金属
膜片开关用银浆制备使用的有机体系中,树脂、溶剂和添加剂对产品的性能和有害元素控制有重要的意义。经对比实悚,以热塑性聚酯为主体树脂,以MEA混合溶剂为溶剂,以YU-201、硅烷偶联剂以及自制增强塑性材料M-17材料为混合添加剂,制成有机载体。使用该载体制备出的浆料符合膜片开关银浆性能要求,且满足欧盟RoHS指标卤素控制要求。
关键词:
复合材料
,
环保型
,
无卤素
,
膜片开关
,
银浆
吕友军
,
董旭斌
,
张天宁
工程热物理学报
本文采用基于颗粒动力学的欧拉双流体模型,对比研究了曳力和湍流对超临界水流化床传热特性的影响,选取了Gidaspow、Syamlal-O'Brien和Wen-Yu三种曳力模型以及标准κ-ε、RNG κ-ε、Realizable κ-ε湍流模型三种高Re数湍流模型及低Re数κ-ε湍流模型.研究结果表明,在三种曳力模型中,Gidaspow曳力模型在超临界水流化床中更为适用;对于所采用的四种κ-ε湍流模型,利用三种高雷诺数湍流模型模拟所得床层与壁面间传热系数基本一致且大于采用低雷诺数模型模拟所得传热系数,而综合考虑,RNGκ-s湍流模型更适于超临水流化床传热特性的研究.
关键词:
超临界水流化床
,
曳力
,
湍流
,
传热
朱奎松
,
刘松利
,
芶淑云
,
王梁
钢铁钒钛
doi:10.7513/j.issn.1004-7638.2017.02.005
基于欧拉-双流体模型和流态化氯化临界流化速度经验公式,结合云南高钛渣物性参数,研究了其流态化氯化的初始流化速度下高钛渣流态化氯化特性、气泡运动对床层的扰动、气泡大小与分布板位置关系.研究结果表明:Grace方程能准确预测B类颗粒窄粒径的高钛渣流态化氯化气泡行为,Wen-Yu方程预测的初始流化速度下乳相和气泡出现时间延后;完全流化速度下,通过上升、合并长大、破裂过程,在分布板位置形成气泡;通过钛渣固体矢量图得出,整个床层以气泡为分界,气泡上升对上、下部颗粒的流动产生影响,导致床层不均匀.
关键词:
四氯化钛
,
高钛渣
,
氯化
,
流化床
,
数值模拟
,
流动特性