材料期刊网

PHYSICAL MODELING FOR THE MECHANISMS OF BEAD FORMATION DEFECTS BASED ON THE STABILITY OF LIQUID METAL

S. Y. Yin , L. Feng , J. Z. Ding and S. J. Chan( 1) Beijing Polytechnic University , Beijing 100022 , China 2) National Key Laboratory of Advanced Wdlding Production Technology , HIT , Harbin 150001 , China)

金属学报(英文版)

Based on the theory of stability of the liquid metal under the action of surface tension,a physical mod- el is established for the mechanisms of the bead formation deferct' humping', which is generated during high - speed welding.A boundary function is introduced to correct the model,theoretical results got by the model correspond well with the experimental phenomena. A two - dimensional conducting model is adoopted in the simulation of the temperature field during high - speed welding.Finally, the factors acting upon the stability of liquid metal are analyzed.

关键词: high - speed welding , null , null

Magnetization, internal energy and specific heat in a three-sublattice ferrimagnet or ferromagnet with vertical bar J(ab)vertical bar=vertical bar J(bc)vertical bar not equal J(ca)

Journal of Physics-Condensed Matter

The temperature dependences of the magnetization, internal energy and specific heat in a three-sublattice ferrimagnet or ferromagnet with /J(ab)/ = /J(bc)/ not equal /J(ca)/ are calculated within the framework of the linear spin-wave approximation, by employing retarded Green's functions. For both the ferromagnet and the ferrimagnet, the internal energy and the specific heat decrease with increasing J ' /J and/or the value of the spins. For fixed values of S,, Sb, S, and J ' /J, the internal energy and the specific heat increase, whereas the sublattice magnetization decreases with increasing temperature theta. The three-sublattice ferrimagnet has some particular characteristics which are not shown by the systems with two sublattices. For ferrimagnets, the antiferromagnetism of the system becomes weaker with increasing J ' /J. The sublattice magnetization at low temperatures (also the magnetization M(0) at 0 K) of a ferrimagnet increases with increasing J ' /J for fixed values of S(a), S(b) and S(c). The effects of the spins S(a) (S,) and Sb On the magnetizations of other sublattices differ. The characteristics of the a-sublattice are the same as those of the c-sublattice, due to their similarity as well as the symmetry of the system. The behaviours of the b-sublattice are different from those of the a- and c-sublattices, due to the asymmetry of the three-sublattice system. The spin-value dependences of the spin deviation Deltam per spin land also the energy for the zero-point quantum fluctuation) of the system are different for different sublattices. These differences are ascribed to the asymmetry of the three-sublattice systems, which leads to the new intrinsic properties of the systems.

关键词: layered heisenberg ferrimagnets;spin-wave theory;elementary;excitations;superlattices;systems;magnetoresistance;antiferromagnet;interfaces

Ion sputter erosion in metallic glass-A response to "Comment on: Homogeneity of Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass" by L-Y. Chen, Y-W. Zeng, Q-P. Cao, B-J. Park, Y-M. Chen, K. Hono, U. Vainio, Z-L. Zhang, U. Kaiser, X-D. Wang, and J-Z Jiang J. Mater. Res. 24, 3116 (2009)

Journal of Materials Research

The morphology of the dark and bright regions observed by transmission electron microscopy for the Zr(64.13)Cu(15.75)Ni(10.12)Al(10) bulk metallic glass strongly depends on the ion beam parameters used for ion milling. This indicates that the ion beam could introduce surface fluctuation to metallic glasses during ion milling.

关键词: room-temperature

S355J2W耐候钢的耐腐蚀性能

鲁二敬 , 卢峰华 , 许鸿吉 , 谢明 , 钮旭晶

机械工程材料

通过周期浸润腐蚀试验，对比研究了S355．12W耐候钢和Q345R低合金钢在NariSOs溶液中的耐腐蚀性能，并用扫描电镜对腐蚀产物进行了观察和分析。结果表明：在相同试验条件下，S355J2W耐候钢的腐蚀速率低于Q345R钢的；S355J2W耐候钢会在表面形成黑褐色锈层，而Q345R钢表面形成橘红色易剥落的疏松锈层；S355J2W耐候钢腐蚀产物微观形貌为沿放射性方向生长的针状晶体，Q345R钢为颗粒状聚合物堆积而成，形状无规则，颗粒之间有较大的空隙。

关键词: S355J2W耐候钢 , 周期浸润腐蚀试验 , 耐腐蚀性能

应力对1J79软磁合金强场磁导率的影响

尔延徽 , 毛昌辉 , 杨志民 , 杜军

稀有金属 doi:10.3969/j.issn.0258-7076.2007.06.008

采用8232型B-H交流回线仪对受力前后的1J79软磁合金在不同场强和频率下磁导率的变化进行了研究, 通过XRD对材料受力前后微观结构变化进行了分析. 研究表明: 场强在1～10 A·m-1范围内, 直流条件下受应力1J79合金的相对磁导率远低于不受应力1J79合金的相对磁导率; 交流条件(5～30 kHz)下受应力1J79合金的相对磁导率低于不受应力1J79合金的相对磁导率, 但低于直流条件下的降低幅度. 1J79合金受力后, 使有利于磁性能(111)晶面取向大大减少, 是合金受力后相对磁导率下降的主要原因.

关键词: 应力 , 强场 , 1J79软磁合金 , 相对磁导率

深低温条件下1J30的马氏体转变研究及TEM分析

宁波 , 赵宇 , 李春志 , 李波

物理测试

对1J30升温和降温过程分析得出，深低温条件下1J30的马氏体转变为不可逆转变。同时，对1J30内马氏体衍射斑点分析得出：有许多平行的极薄的马氏体片生成；马氏体与奥氏体的位相关系符合“西山关系”。对软磁材料中的马氏体研究具有一定的意义。

关键词: 马氏体转变 , crystallographic orientation , twins

深低温条件下1J30的马氏体转变研究及TEM分析

宁波 , 赵宇 , 李春志 , 李波

物理测试

对1J30升温和降温过程分析得出,深低温条件下1J30的马氏体转变为不可逆转变.同时,对1J30内马氏体衍射斑点分析得出:有许多平行的极薄的马氏体片生成;马氏体与奥氏体的位相关系符合"西山关系".对软磁材料中的马氏体研究具有一定的意义.

关键词: 马氏体转变 , 位向关系 , 孪晶

数理统计方法在1J85软磁合金生产中的应用

段晓昆 , 姜燕 , 胡军

金属功能材料

本文介绍了利用数理统计方法中的相对频数曲线,统计、分析实际生产中1J85软磁合金主要化学成分的分布情况,找出影响1J85软磁合金初始磁导率的因素,并采取了相应的改进措施,使1J85软磁合金产品的初始磁导率有了显著的提高.

关键词: 数理统计 , 相对频数曲线 , 1J85软磁合金 , 初始磁导率

S355J2钢板表面裂纹成因分析及控制

孙雪娇 , 高立福 , 刘金超 , 闵凡启 , 张婷

物理测试 doi:10.13228/j.boyuan.issn1001-0777.20150106

针对S355J2钢板表面出现裂纹缺陷的现象,采用金相显微镜、扫描电镜、能谱仪等检验手段分别从表面裂纹形貌、非金属夹杂物、组织分布等方面进行一系列分析.结果表明:裂纹起源于结晶器保护渣的卷入,并且在加热保温过程中裂纹两侧发生了脱碳以及内氧化.

关键词: S355J2钢 , 表面裂纹 , 脱碳层 , 内氧化

不同热处理方法对1J50合金软磁性能影响研究

张燕阳 , 王德义 , 詹晓梅 , 谭常灵

材料开发与应用 doi:10.3969/j.issn.1003-1545.2012.02.006

1J50软磁合金良好的磁性能主要是通过合适的热处理工艺方法得到的,用金相显微镜、XRD等对不同热处理工艺的1J50软磁合金的组织结构进行了分析,用MATS - 2010SA软磁测试仪对1J50软磁合金的磁性能进行了检测.结果表明,不同热处理工艺方法得到的1J50软磁合金组织和性能存在比较明显的差异.氢气气氛热处理得到的合金软磁性能优异.

关键词: 热处理 , 1J50合金 , 组织结构 , 性能