This study systematically investigated the microstructural evolution of binary Ni-Cu alloys(Cu55Ni45,Cu60Ni40,and Ni65Cu35)under deep undercooling conditions.The controlled rapid solidification experiments combined wi...This study systematically investigated the microstructural evolution of binary Ni-Cu alloys(Cu55Ni45,Cu60Ni40,and Ni65Cu35)under deep undercooling conditions.The controlled rapid solidification experiments combined with optical microscopy and electron backscatter diffraction(EBSD)analysis demonstrate that increasing undercooling(ΔT)can induce a consistent sequence of microstructural transitions:coarse dendrites,fine equiaxed grains(first refinement),oriented fine dendrites,and fine equiaxed grains(second refinement).Two distinct grain refinement events are identified,with critical undercooling thresholds(ΔT)dependent on composition:increasing Cu content increases the critical undercoolingΔT*required for the second refinement(Cu55Ni45:227 K;Cu60Ni40:217 K;Ni65Cu35:200 K).The BCT(Bridgman Crystal Growth)model quantitatively elucidates this behavior,revealing a shift from solute-diffusion-dominated growth at low undercooling to thermally dominated diffusion at high undercooling(ΔT).Crucially,refined grains at high undercooling exhibit smaller sizes(10μm)and higher uniformity than those at low undercooling(20μm).These findings provide fundamental insights into non-equilibrium solidification mechanisms and establish a foundation for designing high-performance Ni-Cu alloys via deep undercooling processing.展开更多
The Ba（0.96）Ca（0.04）Ti（0.90）Sn（0.10）O3-xNd2 O3（x = 0-0.08%） ceramics were prepared via traditional solid-state sintering method. The influences of Nd3＋ substitution on the phase structure, dielectric proper...The Ba（0.96）Ca（0.04）Ti（0.90）Sn（0.10）O3-xNd2 O3（x = 0-0.08%） ceramics were prepared via traditional solid-state sintering method. The influences of Nd3＋ substitution on the phase structure, dielectric properties,piezoelectric and ferroelectric properties of the ceramics were investigated. All the samples possess pure BaTiO3-type perovskite structure. MPB with orthorhombic and tetragonal phase coexist at around x = 0.03-0.04. Nd^（3＋） doping decreases both Tc and T（O-T） to lower temperature. All the samples exhibit an intermediate state with the coexistence of ferroelectric and diffuse relaxor ferroelectric behavior with the addition of Nd^（3＋）. The electric properties of the ceramics were optimized at x = 0.03 with d33, Kp, εr and Pr values of 545 pC/N, 51.9%, 24,412 and 10.74 μC/cm^2.展开更多
2005年4月2日，英国Trinity Asia Limited(简称TAL)与其投资成立的北京石生伟业S-BCT仿生轮胎(中国)项目中心在北京宣布，面向中高档轿车市场的第2代高科技仿生轮胎BCT(图1)，并在首创轮胎有限责任公司实现了生产。据介绍，经美国史密...2005年4月2日，英国Trinity Asia Limited(简称TAL)与其投资成立的北京石生伟业S-BCT仿生轮胎(中国)项目中心在北京宣布，面向中高档轿车市场的第2代高科技仿生轮胎BCT(图1)，并在首创轮胎有限责任公司实现了生产。据介绍，经美国史密斯科学服务公司、清华大学汽车工程系、中国汽车质量北方监督检验所、国家橡胶轮胎质量监督检验测试中心检测，展开更多
This work deals with a second order linear general equation with partial derivatives for a two-variable function. It covers a wide range of applications. This equation is solved with a finite difference hybrid method:...This work deals with a second order linear general equation with partial derivatives for a two-variable function. It covers a wide range of applications. This equation is solved with a finite difference hybrid method: BTCS + CTCS. This scheme is simple, precise, and economical in terms of time and space occupancy in memory.展开更多
基金Funded by the Central Government-Guided Local Development Fund Project(No.YDZJSX2025D042)the Key R&D Program of Shanxi Province(No.202202150401018)+1 种基金the Basic Research Program of Shanxi Province(No.20210302124220)the State Key Laboratory of CAD/CG of Zhejiang University(No.A2325)。
文摘This study systematically investigated the microstructural evolution of binary Ni-Cu alloys(Cu55Ni45,Cu60Ni40,and Ni65Cu35)under deep undercooling conditions.The controlled rapid solidification experiments combined with optical microscopy and electron backscatter diffraction(EBSD)analysis demonstrate that increasing undercooling(ΔT)can induce a consistent sequence of microstructural transitions:coarse dendrites,fine equiaxed grains(first refinement),oriented fine dendrites,and fine equiaxed grains(second refinement).Two distinct grain refinement events are identified,with critical undercooling thresholds(ΔT)dependent on composition:increasing Cu content increases the critical undercoolingΔT*required for the second refinement(Cu55Ni45:227 K;Cu60Ni40:217 K;Ni65Cu35:200 K).The BCT(Bridgman Crystal Growth)model quantitatively elucidates this behavior,revealing a shift from solute-diffusion-dominated growth at low undercooling to thermally dominated diffusion at high undercooling(ΔT).Crucially,refined grains at high undercooling exhibit smaller sizes(10μm)and higher uniformity than those at low undercooling(20μm).These findings provide fundamental insights into non-equilibrium solidification mechanisms and establish a foundation for designing high-performance Ni-Cu alloys via deep undercooling processing.
基金supported by the National Natural Science Foundation of China(51702024)Sci-Tech Support Plan-Social Development of Changzhou City(CE20175041)the Priority Academic Program Development of Jiangsu Higher Education Institutions(15KJA43002)
文摘The Ba（0.96）Ca（0.04）Ti（0.90）Sn（0.10）O3-xNd2 O3（x = 0-0.08%） ceramics were prepared via traditional solid-state sintering method. The influences of Nd3＋ substitution on the phase structure, dielectric properties,piezoelectric and ferroelectric properties of the ceramics were investigated. All the samples possess pure BaTiO3-type perovskite structure. MPB with orthorhombic and tetragonal phase coexist at around x = 0.03-0.04. Nd^（3＋） doping decreases both Tc and T（O-T） to lower temperature. All the samples exhibit an intermediate state with the coexistence of ferroelectric and diffuse relaxor ferroelectric behavior with the addition of Nd^（3＋）. The electric properties of the ceramics were optimized at x = 0.03 with d33, Kp, εr and Pr values of 545 pC/N, 51.9%, 24,412 and 10.74 μC/cm^2.
文摘2005年4月2日，英国Trinity Asia Limited(简称TAL)与其投资成立的北京石生伟业S-BCT仿生轮胎(中国)项目中心在北京宣布，面向中高档轿车市场的第2代高科技仿生轮胎BCT(图1)，并在首创轮胎有限责任公司实现了生产。据介绍，经美国史密斯科学服务公司、清华大学汽车工程系、中国汽车质量北方监督检验所、国家橡胶轮胎质量监督检验测试中心检测，
文摘This work deals with a second order linear general equation with partial derivatives for a two-variable function. It covers a wide range of applications. This equation is solved with a finite difference hybrid method: BTCS + CTCS. This scheme is simple, precise, and economical in terms of time and space occupancy in memory.
