High-speed milling of titanium alloys using binderless CBN tools

The performance of conventional tools is poor when used to machine titanium alloys. In this paper, a new tool material, which is binderless cubic boron nitride (BCBN), is used for high-speed milling of a widely used titanium alloy Ti–6Al–4V. The performance and the wear mechanism of the BCBN tool have been investigated when slot milling the titanium alloy in terms of cutting forces, tool life and wear mechanism. This type of tool manifests longer tool life at high cutting speeds. Observations based on the SEM and EDX suggest that adhesion of workpiece and attrition are the main wear mechanisms of the BCBN tool when used in high-speed milling of Ti–6Al–4V.     

金属及合金中钛的光度分析近况

综述了金属及合金中钛的光度测定方法新近进展情况。     

碳纳米管及稀土元素钇(Y)对高Ni含量Ti(C,N)基金属陶瓷组织与性能的影响

研究了不同含量的碳纳米管及0.8%稀土Y对高Ni含量Ti(C,N)基金属陶瓷组织性能的影响.将不同成分的试样分别于1400℃、1410 ℃、1420℃真空烧结,测试抗弯强度、洛氏硬度,观察背散射电子形貌、断口形貌并做能谱分析.结果表明,加入质量分数(下同)为0.8%Y及0.3%～1.0%的碳纳米管时,碳纳米管含量为0.5%的组织较均匀,芯壳结构明显,抗弯强度及硬度均较高.     

浸渗工艺对SiC/Al复合材料残余气孔率的影响

采用无压浸渗法制备了SiC/Al复合材料,从浸渗动力学和工艺方法的角度探讨了浸渗保温时间和降温方式对复合材料的残余气孔率的影响。结果表明:随着保温时间的适当延长,能有效地降低复合材料的残余气孔率;连续降温优于分段降温,有利于降低SiC/Al复合材料的残余气孔率。     

Stability of AB5-type hydrogen storage alloys

In this paper, we deduced an empirical equation for predicting the stabilities of the hydrides of AB₅-type compounds with the consideration of the effects of geometrical factor and electric factor. The theoretical curves derived from this equation are in good agreement with the test results of La_1−xCa_xNi₅, Ml_1−xCa_xNi₅ and La_1−xCe_xNi₅ compounds. With this model, we can easily interpret the phenomenon that the initial partial substitution of R by Ca in R_1−xCa_xNi₅ (R is rare earth metal) compounds cause an increase of hydrogen desorption pressure to a maximum value, whereas in the range of larger Ca content x the hydrogen desorption pressure decreases with increasing x.     

Strengthening technology and mechanism for semi-solid die casting of aluminum alloy

Combined with theoretical evaluation,an optimized strengthening process for the semi-solid die castings of A356 aluminum alloy was obtained by studying the mechanical properties of castings solution treated and aged under different conditions in detail,then,the semi-solid die castings and liquid die castings were heat treated with the optimized process.The results show that the mechanical properties of semi-solid die castings of aluminum alloy are superior to those of the liquid die castings,especially the strengthening degree of heat treated semi-solid die castingsis much greater than that of liquid die castings with the tensile strength more than 330 MPa and the elongation more than 10％,and this is mainly contributed to the non-dendritic and more compact microstructure of semi-solid die castings.The strengthening mechanism of heat treatment for the semi-solid die castings of A356 aluminum alloy is due to the dispersive precipitation of the second phase(Mg2 Si) and formation of GP Zone.     

AlF3贮仓料位计在线监控系统开发与应用

针对铝电解原材料中AlF3与Al2O3自动配料不准和难于观察及控制的现象，我厂开发应用了AlF3贮仓料位计，并与微机网络相连，实现了远程测量与在线监控，使AlF3配料更准确更均匀，电解质分子比更稳定，电解槽生产低耗高效。     

粉煤灰填充尼龙6浇铸制品的研究

将粉煤灰用硅烷偶联剂处理后填充到尼龙6浇铸制品(MC尼龙)中,可以改善制品的吸水性、收缩率及热稳定性等,还可以降低成本。该项研究结果有很大的实用价值。     

百菌清及其三氟衍生物对番茄早疫病菌的室内抑菌活性比较

采用生长速率法测定了不同浓度的百菌清及其三氟衍生物对番茄早疫病菌Alternaria solani(Ell,et Mart.)Jones es Gmut的室内杀菌毒力。试验结果表明，百菌清及其三氟衍生物的ED50值分别为6089．89mg／L和156．43mg/L。，前者是后者的38．93倍。百菌清三氟衍生物的毒力明显高于百菌清。