为分析影响热变形钕铁硼磁体矫顽力的因素,制备了3种不含Dy,Ga热变形磁体,磁体成分分别为Nd10.5Pr2.5Fe80Nb1B6,Nd11.5Fe81.8B6.0Nb0.7+6%Nd67Cu33及Nd10.5Pr2.5Fe80Nb1B6+6%Nd67Cu33,由Nd-Fe-B三元相图计算了富稀土晶界相体积分数v,实...为分析影响热变形钕铁硼磁体矫顽力的因素,制备了3种不含Dy,Ga热变形磁体,磁体成分分别为Nd10.5Pr2.5Fe80Nb1B6,Nd11.5Fe81.8B6.0Nb0.7+6%Nd67Cu33及Nd10.5Pr2.5Fe80Nb1B6+6%Nd67Cu33,由Nd-Fe-B三元相图计算了富稀土晶界相体积分数v,实验结果表明:v对富稀土钕铁硼热变形磁体矫顽力的贡献为98.10 k A·m-1·%-1,比v对贫稀土钕铁硼混粉热变形磁体矫顽力的贡献低36%~44%;由v=1-a3/[(a+h)2(a+3h)]计算了富稀土晶界相厚度h,发现在v相同条件下热变形钕铁硼磁体晶界相厚度h随主相片状晶等效平均晶粒尺寸a的减小虽然减薄,但a占主导作用导致磁体的矫顽力仍然提高;在片状晶等效平均晶粒尺寸a相近的条件下,热变形钕铁硼磁体晶界相厚度随晶界相体积分数v的增加而变厚,主相片状晶的磁绝缘效果提高导致热变形磁体的矫顽力上升。展开更多
A cellular automata (CA) method was employed to model static coarsening controlled by diffusion along grain boundaries at 1173K and through the bulk at 1213 and 1243K for a two-phase titanium alloy. In the CA model, t...A cellular automata (CA) method was employed to model static coarsening controlled by diffusion along grain boundaries at 1173K and through the bulk at 1213 and 1243K for a two-phase titanium alloy. In the CA model, the coarsening rate was inversely proportional to the 3rd power of the average grain radius for coarsening controlled by diffusion along grain boundaries, and inversely proportional to the 2nd power of the average grain radius for coarsening controlled by diffusion through the bulk. The CA model was used to predict the morphological evolution, average grain size, topological characteristics, and the coarsening kinetics of the Ti-6Al-2Zr-1Mo-1V (TA15) alloy during static coarsening. The predicted results were found to be in good agreement with the corresponding experimental results. In addition, the effects of the volume fraction of the phase (Vf ) and the initial grain size on the coarsening were discussed. It was found that the predicted coarsening kinetic constant increased with Vf and that a larger initial grain size led to slower coarsening.展开更多
基金the National Natural Science Foundation of China(Nos.51675414,51805416)the Joint Fund for Aerospace Advanced Manufacturing Technology Research Key Program,China(No.U1937203).
文摘为分析影响热变形钕铁硼磁体矫顽力的因素,制备了3种不含Dy,Ga热变形磁体,磁体成分分别为Nd10.5Pr2.5Fe80Nb1B6,Nd11.5Fe81.8B6.0Nb0.7+6%Nd67Cu33及Nd10.5Pr2.5Fe80Nb1B6+6%Nd67Cu33,由Nd-Fe-B三元相图计算了富稀土晶界相体积分数v,实验结果表明:v对富稀土钕铁硼热变形磁体矫顽力的贡献为98.10 k A·m-1·%-1,比v对贫稀土钕铁硼混粉热变形磁体矫顽力的贡献低36%~44%;由v=1-a3/[(a+h)2(a+3h)]计算了富稀土晶界相厚度h,发现在v相同条件下热变形钕铁硼磁体晶界相厚度h随主相片状晶等效平均晶粒尺寸a的减小虽然减薄,但a占主导作用导致磁体的矫顽力仍然提高;在片状晶等效平均晶粒尺寸a相近的条件下,热变形钕铁硼磁体晶界相厚度随晶界相体积分数v的增加而变厚,主相片状晶的磁绝缘效果提高导致热变形磁体的矫顽力上升。
基金supported by the National Natural Science Foundation of China (50935007, 51175428)the National Basic Research Program of China (2010CB731701)+1 种基金the Foundation for Fundamental Research of Northwestern Polytechnical University in China (NPU-FFR-JC20100229)the Center for Foreign Talent Introduction and Academic Exchange for Advanced Materials and Forming Technology Discipline Project (B08040)
文摘A cellular automata (CA) method was employed to model static coarsening controlled by diffusion along grain boundaries at 1173K and through the bulk at 1213 and 1243K for a two-phase titanium alloy. In the CA model, the coarsening rate was inversely proportional to the 3rd power of the average grain radius for coarsening controlled by diffusion along grain boundaries, and inversely proportional to the 2nd power of the average grain radius for coarsening controlled by diffusion through the bulk. The CA model was used to predict the morphological evolution, average grain size, topological characteristics, and the coarsening kinetics of the Ti-6Al-2Zr-1Mo-1V (TA15) alloy during static coarsening. The predicted results were found to be in good agreement with the corresponding experimental results. In addition, the effects of the volume fraction of the phase (Vf ) and the initial grain size on the coarsening were discussed. It was found that the predicted coarsening kinetic constant increased with Vf and that a larger initial grain size led to slower coarsening.
