张英逊
,
卢晓华
,
赵凯
,
李祝霞
,
P．Danielewicz
,
M．B．Tsang
原子核物理评论
对称能的密度依赖形式对于中子星结构及其演化规律、不稳定核结构及其反应等都有非常重要的影响。由于目前理论上预言的对称能密度依赖形式有很大的不确定性,因此确定对称能的密度依赖形式已经成为目前核物理研究的一个重要课题。丰中子核重离子碰撞是目前在实验室条件下确定对称能密度依赖形式的一种重要手段,其主要的理论依据就是微观输运理论。首先回顾了目前输运理论的两个处理方法,即Boltzmann-Uehling-Uhlenbeck（BUU）和量子分子动力学（QMD）方法,并重点介绍了改进的量子分子动力学模型（ImQMD05）。利用ImQMD05对中能重离子碰撞的一些基本观测量,如碎块分布、集体流、核核碰撞的阻止本领等进行了详细研究,通过与实验数据的比较,确定了ImQMD05中同位旋无关部分的平均场、介质中核子-核子散射截面。为了从重离子碰撞的实验数据确定对称能的密度依赖形式,详细研究了输运理论中对称势以及同位旋相关的介质中核子-核子散射截面对于同位旋敏感观测量的影响。研究显示,对于Fermi能附近的重离子碰撞,输运理论预言的同位旋敏感的观测量,如DR（n/p）和Ri,强烈依赖于对称势的软硬,而不敏感于介质中同位旋相关的核子-核子散射截面。多重碎裂作为中能重离子碰撞的一个主要特点,本文论述的研究显示碎块发射机制对同位旋敏感的观测量,出射核子的双中子质子之比DR（n/p）和同位旋转移之比Ri,都有重要影响。以重碎块的同位旋不对称度为探针得到的同位旋转移之比Ri（δZmax〉20）要大于Ri（δ）,这些测量能够在NSCL/RIKEN的相关实验上进行测量。同时,这一现象的研究对于理解碎块的发射机制及碎块发射的特征时间等问题将有重要的帮助。为此,采用ImQMD05研究了112,124Sn＋112,124Sn在入射能量50MeV/u,不同碰撞参数条件下的多个实验观测量,如DR（n/p）、同位旋扩散Ri以及同位旋转移之比的快度分布。研究表明,模型能够同时自洽地解释这几个实验观测量,并通过与这些实验数据的分析比较,自洽地确定出低密区对称能密度依赖形式的范围。
关键词:
对称能
,
重离子碰撞
,
集体流
,
核核碰撞的阻止本领
Materials Letters
The effects of P and B on the creep behavior of 718 alloys are discussed in this paper. The result implies that P and B have little effect on the gamma" and gamma' phases of the alloy, but they can enhance the grain boundary strength by segregating there, which can be of beneficial to the higher creep properties. P also may increase the grains strength through solid solution. The beneficial effect of P and B were presented in both standard IN718 alloy and DA718 alloy. Adding P and B together does a better work than adding P alone. (c) 2006 Elsevier B.V. All rights reserved.
关键词:
P and B;718 alloy;creep;grain boundaries;heat treatment;stress rupture;phosphorus;superalloy;boron
宿辉
,
蔡伟
,
曹茂盛
材料科学与工艺
doi:10.3969/j.issn.1005-0299.2008.03.004
为解决Ni-P-(SiC)P镀层中基体的金属键与增强体的共价键间相容性差,增强体颗粒易脱落,镀层性能降低等问题.采用简单的化学镀方法实现了(SiC)P表面修饰、改性,得到了涂覆型改性(Ni/SiC)P,以(Ni/SiC)P为第二相粒子制备了Ni-P-(Ni/SiC)P化学复合镀层,并初步分析了复合镀机理.实验结果表明:温度、pH值、搅拌速率及(Ni/SiC)P加入量对Ni-P-(Ni/SiC)P镀层的沉积速率及沉积量有较大的影响,本实验条件下的最佳温度为82～86℃;最佳pH值为4.2～4.6;最佳搅拌速率为200 r/mim;最佳粒子加入量10 g/L.SEM、EDS分析显示Ni-P-(Ni/SiC)P镀层均匀、致密,Ni、P、Si沉积量大,耐磨性实验证明Ni-P-(Ni/SiC)P化学复合镀层硬度、耐磨性优干常见的Ni-P、Ni-P-(SiC)P镀层.经表面修饰、改性后得到的(Ni/SiC)P可以进一步提高Ni-P-(SiC)P镀层的使用性能.
关键词:
化学镀
,
(Ni/SiC)P
,
镀层
,
工艺条件
,
耐磨性
宿辉
,
蔡伟
,
曹茂盛
材料工程
doi:10.3969/j.issn.1001-4381.2007.10.010
为解决裸(SiC)p在实际应用中存在的不足,采用简单的化学镀方法对其表面进行改性,得到了包覆型的改性(Ni/SiC)p,以(Ni/SiC)p为第二相粒子制备了Ni-P-(Ni/SiC)p化学复合镀层,经扫描电镜、能量散射仪、硬度等测试,并与常见的Ni-P化学镀层、Ni-P-(SiC)p化学复合镀层比较,结果显示:Ni-P-(Ni/SiC)p镀层具有组成均匀、硬度高、镀层耐磨损等优点,为(SiC)p增强金属镀层及基体材料的研究提供了一个新的思路.
关键词:
化学镀
,
(Ni/SiC)p
,
镀层
,
硬度
NING Hua ZHANG Lixin Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang
,
China
金属学报(英文版)
The segregation behaviour of P and its effect on structure of 70%-reduction cold rolled Fe-P alloys containing different contents of P,e.g.,0.007,0.06 and 0.09% P,during annealing at 200-700℃ under vacuum have been studied by means of metallography and EPMA.The P was found to segregate preferentially along dislocation line during recovery annealing.The P-riched dislocation densing region,the P-depleted region and the sub-grain-like boundary thus formed.The nuclei grow preferentially during recrystallization in such region that the P segregation is more evident and the residual strain by dislocation densing increases to large extent.After recrystallizing,the P segregates along grain boundaries and makes the grains in alloy fine. Engineer,Institute of Corrosion and Protection of Metals,Academia Sinica,Shenyang 110015,China
关键词:
P
,
null
,
null
,
null
韩其勇
,
张晓东
,
王鹏飞
,
王杰
,
陈冬
金属学报
用Ca与P合成的Ca_3P_2,在1600℃通过Ca_3P_2的分解,测定了纯Fe液中Ca-P平衡常数和活度相互作用系数,得到 K_(Ca_3P_2)=α_(Ca)~3·α_P~2=7.0×10~(-14) e_P~(Ca)=-3.1
关键词:
Ca-P平衡
,
Ca P
赵芳霞
,
刘琛
,
张振忠
,
丘泰
材料保护
doi:10.3969/j.issn.1001-1560.2006.03.020
利用SEM、DSC、XRD、中性盐雾试验和显微硬度分析等手段,对Ni-10.54%P及Ni-9.25%Cu-10.23%P化学镀层的组织特征、相结构转变、热稳定性、耐蚀性和硬度进行了比较.结果表明:(1)两种镀层均匀致密,均为胞状结构和非晶态组织;(2)Ni-P镀层仅发生从非晶相向稳定的Ni3P相转变,而Ni-Cu-P镀层则先生成Ni-Cu固溶体和亚稳中间相Ni5P2,再向稳定相Ni3P转变;(3)Ni-Cu-P镀层的热稳定性高于Ni-P镀层;(4)镀态和低温热处理条件下两种镀层的硬度相差不大,Ni-P镀层经400 ℃、60 min热处理时硬度达到最高值981.1 HV,但Ni-Cu-P镀层经500 ℃、60 min热处理时硬度达到最高值1 144.8 HV;(5)镀态时Ni-Cu-P镀层的腐蚀速率只有Ni-P镀层腐蚀速率的2.85%;经过400 ℃、120 min相同条件的热处理,Ni-Cu-P镀层的腐蚀速率仅为Ni-P镀层腐蚀速率的0.351%.
关键词:
化学镀
,
Ni-P
,
Ni-Cu-P
,
热稳定性
,
硬度
,
耐蚀性
ZHANG Lixin NING Hua Laboratory of Corrosion Science
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica.Shenyang
,
ChinaZHOU Jing LI Liguang Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
China Professor
,
Institute of Corrosion and Protection of Metals
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
The relations between the non-equilibrium segregation process of P and the change of the texture in Fe-P alloys have been studied by analytical electron microscope and orientation distribution function.It was shown that P segregated preferentialy on the{110}slip planes, the P segregation structures with repeating cycle a=1.582 nm form at 450℃.<001>// ND direction abated.<111>//ND direction heightened.And{111}<110>has a tendancy to transform into{111}<143>texture in recovering process.{111}<143>direction trans- forms into{111}<112>direction after recrystalizing.A model to describe the effects of non-equilibrium segregation structures of P on orientation change was proposed and em- ployed to interpret the experiment results.
关键词:
Fe-P Alloy
,
null
,
null
,
null
