王晓峰
,
赵九洲
,
何杰
,
王江涛
金属学报
在群体动力学的基础上，提出了描述Cu-13.5%Sn(质量分数)合金雾化液滴凝固过程的动力学模型; 并将其与液滴的传热方程和运动方程相耦合，对雾化液滴的冷却凝固过程进行了模拟分析，探讨了液滴尺寸、气体初始速度、熔体过热度和初生相与异质形核基底间润湿角对液滴凝固行为的影响. 模拟结果表明：本模型能够很好地描述雾化液滴的凝固过程; 液滴冷却至一定温度开始形核，随后晶粒长大；液滴直径越小，冷却速度越快，液滴内晶粒数量密度就越高，凝固结束时晶粒亦越细小. 形核润湿角和熔体过热度的增加，导致液滴内晶粒数量密度降低，晶粒半径增大; 而气体初始速度的增加，有利于液滴内晶粒细化.
关键词:
Cu-13.5%Sn合金
,
spray forming
,
population dynamics
J.F. Sun
,
J. Shen
,
Z. Y. Li
,
J. Jia and Q.C. Li National Key Laboratory of Metal Precision Hot Processing
,
Harbin Institute of Technology
,
Harbin 150001
,
China
金属学报(英文版)
Based on the Newtonian heat transfer formulation and classical heterogeneous nucleation theory, a mathematical model has been established to predict the profile of flight velocity, heat transfer coefficient, temperature, solid fraction and cooling rate of atomizing droplets for a superalloy. The results indicated that above parameters change with different droplet size and flight distance. The changing trend as well as the mechanism for the change are described and discussed.
关键词:
spray forming
,
null
,
null
,
null
Z. Li
,
G.Q. Zhang
,
Z.H. Zhang
,
S.F. Tian
金属学报(英文版)
In order to evaluate the deformation characteristics of spray formed superalloy GH742
and determine the appropriate forging procedure of the alloy on this basis, the influence
of deformation temperature and strain rate on the ductility of spray formed GH742
was investigated by using the Gleeble-3500 thermal-mechanical testing machine. It is
shown that the forgeability of spray formed GH742 is better than conventional GH742
by ingot metallurgy because of refined grain structure and enhanced chemical homo-geneity of spray formed GH742. In the temperature range of 1020 to 1100℃, the
ductility of spray formed GH742 is dependent on the deformation temperature and is
increased linearly in proportion to the increment of deformation temperature, which
is more than 40% at 1020℃ and more than 60% at the temperature between 1100
and 1140℃. Furthermore, the results indicate the flow stress is affected considerably
by the deformation temperature and strain rate. In the temperature range of 1020 to
1140℃, the maximum flow stress of spray formed GH742 increases with the increment
of strain rate and decreases with the increment of the deformation temperature.
关键词:
spray forming
,
null
,
null
,
null
C.D.Zhou
,
J.F.Fan
,
H.R.Le
,
Y.J.Lin
,
D.S.Sun
,
J.G.Zhang
金属学报(英文版)
The mechanical properties and microstructure characteristics of a high speed steel (HSS) for roll has been studied. As compared with the as-cast HSS, the spray-formed HSS have fine grain and segregation free microstructures. Carbides distribute uniformly. The morphology and types of the carbides in spray-formed HSS are different from those in as-cast HSS. The results of the high temperature tensile experiment show that, as to spray-formed HSS, there is a possibility of superplastic deformation in the range of 780-810
关键词:
spray forming
,
null
,
null
司朝润
,
张贤杰
,
王俊彪
功能材料
doi:10.3969/j.issn.1001-9731.2015.01.001
喷射成形是将熔融金属雾化和沉积过程相结合，直接由熔融金属制备具有快速凝固组织特征坯体的新型金属材料成形工艺。被引入到非连续增强体金属基复合材料制备领域后，先后发展出了预混喷射成形、反应喷射成形和喷射沉积等工艺方法。介绍了上述颗粒增强金属基复合材料喷射成形工艺方法的基本原理、特点及研究现状。通过对比分析发现喷射沉积技术由于其成形条件限制较少，适用范围广等特点得到了更为广泛的发展，最后结合自身研究对传统喷射沉积技术进行了一定的改进，采用气体-增强颗粒两相流作为雾化介质以期获得提高雾化效率和改善增强颗粒分布均匀性的双重效果。
关键词:
喷射成形
,
快速凝固
,
金属基复合材料
,
颗粒增强体
刘敬福
,
李荣德
机械工程材料
采用喷射成形技术和普通铸造方法制备了合3.5%Mn的ZA35合金,在沸水中研究两种形态合金的腐蚀行为.结果表明:喷射成形态合金腐蚀动力学曲线为抛物线型,其速率常数为2.14×10_(-3) me_2·cm_(-4)·s_(-1),腐蚀速率远远低于符合直线动力学规律的铸态合金;铸态合金腐蚀产物中含有MnO相,而喷射成形态合金的腐蚀产物中未出现MnO相;铸态合金中MnAl_6多存在于晶界,η相和MnAl_6为阴极,α相为阳极优先溶解;喷射成形态合金无MnAl_6相析出,组织均匀细小,α相作为阳极溶解时,腐蚀产物Al(OH)_3很容易在作为短路扩散的细小晶界上产物阻挡,阻止侵蚀性介质的进入,从而减缓腐蚀.
关键词:
喷射成形
,
ZA35-3.5Mn合金
,
沸水
,
腐蚀行为
李元元
,
肖志瑜
,
刘允中
,
李小强
,
杨超
中国材料进展
针对粉末冶金行业最新发展的几种短流程成形固结新技术，结合华南理工大学近十多年来在粉末材料-工艺-装备-零件一体化方面开展的研究，重点阐述了粉末冶金温压成形、高速压制成形、喷射成形、多场作用下粉末成形与烧结一体化技术的研究进展及应用情况。指出在粉末冶金成形固结研究领域，合理拓展现有粉末冶金技术规范的空间，有望给传统粉末冶金成形固结技术注入新的活力。粉末冶金成形固结新技术的不断出现，必将促进先进制造业和高技术产业的快速发展，也必将给材料工程和制造业带来更加光明的前景。
关键词:
粉末冶金
,
温压
,
高速压制
,
喷射成形
,
多场成形与烧结
