多功能移动式防腐保温生产线技术研究

论述了可移动防腐保温生产线的特点及实际应用情况，对预制企业由工厂化生产转向现场预制具有一定的指导意义。     

Worker Exposure Monitoring of Suspended Particles in a Thermal Spray Industry

The purpose of the present work was the investigation and characterization of the quality of air in a thermal spray industry, in Greece. The activities that take place in the specific facility, as well as in most other similar industries, include thermal spraying and several mechanical and metallurgical tasks that generate airborne particles, such as grit-blasting, cutting and grinding of metallic components. Since the main focus of this work was the workers exposure to airborne particles and heavy metals, portable air samplers with quartz fiber filters, were used daily for 8 h. Three samplers, carried from different employees, were used for a period of 1 month. Results showed that both particles and heavy metals concentrations were low, even in the production site, which was the most susceptible area. The only exceptions were observed in the case of cleaning and maintenance activities in the thermal spray booth and in the case of spraying outside the booth. The main reason for the low concentrations is the fact that most of the activities that could produce high-particle concentrations are conducted in closed, well-ventilated systems. Statistical elaboration of results showed that particles are correlated with Ni, Cu, Co. The same conclusion is extracted for Fe, Mn. These correlations indicate possible common sources.     

连续纤维增强钛基复合材料热残余应力的研究进展

综合论述了连续纤维增强钛基复合材料热残余应力的分析方法如：X射线衍射和中子衍射方法、剥层法、基片弯曲法以及选择基体腐蚀法等，以及热残余应力对复合材料力学性能的影响。就热残余应力的影响因素总结了人们在降低复合材料热残余应力方面所作的各种努力，在此基础上指出了当前研究存在的缺陷和今后的发展方向。     

闭孔泡沫铝的导热性能

研究了孔隙率、孔径对闭孔泡沫铝合金导热系数的影响，结果表明，由于大量孔洞的存在，泡沫铝的导热系数较同样成分的实体材料显著下降，孔隙率在0．80—0.93范围内，约为实体材料的1／30—1／80，随着孔隙率的增加，导热系数迅速下降，而孔径对泡沫铝的导热系数影响不大．从串-并联和并-串联模型出发，分析了孔隙率对泡沫铝材料导热系数的影响，发现串-并联模型更能反映泡沫铝的结构特征，与实测值吻合更好。     

Effect of melt pulse electric current and thermal treatment on A356 alloy

Effects of the melt pulse electric current and thermal treatment on solidification structures of A356 alloy were investigated.In the experiments.the low temperature melt(953K and 903K)treated by pulse electric current was mixed with high temperature metl(1223K).By the control experiments,the results show that the solidification structure of A356 alloy is refined apparently by the pulse electric current together with melt thermal treatment process,and the mechanical properties.especially the elongation ratio of the specimen treated is improved greatly.The structure change of the melt by pulse electric current and melt thermal treatment is the main reason for the refinement of the solidification structure of A356 alloy.     

磁性Fe-Cr纤维的长期稳定性和热稳定性

以Cu-Fe-Cr原位复合丝材萃取得微米级、亚微米级的Fe-Cr纤维,并研究了变形量、长期储存条件和热处理对Fe-Cr纤维样品结构和磁性能的影响。采用X射线衍射(XRD)和扫描电镜(SEM)分析了样品的结构和形貌,采用振动样品磁强计(VSM)测试了样品的磁性,并利用热重差热分析(TGA-DTA)比较了不同变形量的Fe-Cr纤维在空气中的热稳定性。结果表明:随着变形量的增大和Fe-Cr纤维的细化,纤维的饱和磁矩基本恒定(约140 A.m2/kg),而剩磁和矫顽力则逐渐增加;Fe-Cr纤维在无水乙醇和空气中储存一年以上,磁性基本保持不变;Fe-Cr纤维在空气中经300℃以上加热1 h后,逐渐由铁磁性的-(αFe,Cr)(BCC结构)固溶体转变为顺磁性的(Fe,Cr)2O3(六角晶系),饱和磁化强度显著下降;且随着变形量的增大,较细Fe-Cr纤维的热稳定性较差。     

数控机床热误差模型的研究进展

综述了数控机床热误差模型的研究现状,从热误差模型的类型、优化模型变量建模、综合误差模型、在线热误差模型等方面将已有模型加以分类并进行分析。在此基础上结合我们的工作提出了今后的设想。探讨了数控机床热误差模型研究中尚存在的热误差模型优化问题、模型参数选择问题、边界条件界定问题和在线研究问题以及相关思路。     

Mechanical strength of PET fibers treated in cold plasma and thermal exposed

As a followup to previous work, experiments with argon and oxygen Radio Frequency plasma treated polyethylene terepthalate (PET) exposed to 100 °C after cold plasma treatment were performed. Tensile tests results in monofilaments treated in oxygen and argon plasma for 5 s, 20 s, 30 s, and 100 s showed a decrease in the average tensile strength compared with the untreated fibers. It was also observed that the reduction in mechanical strength is more significant for argon plasma and very sensitive to the treatment time for oxygen plasma. Experimental data obtained from tensile tests in samples thermal exposed to 100 °C after plasma treatments indicate the same influence of treatment times on mechanical strength, as observed for cold plasma treated fibers. Furthermore, an increase in tensile strength when compared with the samples unexposed to 100 °C was observed. Scanning electron microscopy, used to analyze effects of cold plasma treatment on fibers surfaces, indicates differences in roughness profiles depending on the type of treatment. The distance of roughness interval, D_ri, was a parameter introduced to relate the fibers surface condition and average tensile strength. Statistical analysis of experimental data was performed to explain influences of treatment time, and environmental and temperature effects on mechanical properties.     

热处理对球磨LaNi5-15%Mg合金相组成及热稳定性的影响

采用X-射线衍射仪(XRD)、扫描电子显微镜(SEM)、示差热分析仪(DTA)研究了热处理对球磨LaNi5-15%(质量分数,下同)Mg合金的组织形貌、结构变化及热稳定性的影响.结果表明,经250r/min球磨250h,样品由La、Mg、Ni非晶体及微量的晶体Ni、MgNi2组成,其DTA曲线上只出现了一个峰值温度为564.0K的放热峰.球磨粉末为规则的球形或近球形,颗粒直径范围为0.05～9.00μm,其中94%的颗粒尺寸为0.05～1.00μm;经763K×35天热处理后,样品由具有纳米尺度的MgNi2、LaMg2Ni9、Mg2NiLa三相组成,其平均晶粒直径为21.7nm,热处理样品的DTA曲线上没有吸热或放热峰出现,具有较好的热稳定性能.     

考虑热不协调性的镍基单晶合金细观力学分析SCIEI

基于镍基单晶合金的细观结构特征，本文建立两个微胞模型对热不协调性作了系统的模型计算和分析．微胞模型１是以一个γ和γ’为考察对象，微胞模型２是以多个γ和γ’为考察对象，详细的分析表明，这两个模型有一定的等效性，但模型２可分析边界条件更宽的情况．基于微胞模型，对两相合金的临界分切应力进行了分析，结果表明，宏观临界分切应力可用考虑热不协调性的有限元法来处理，所得结果还可推广到较大的γ’相体积分数ｆ的情况．考察了热不协调性对回火状态时γ’形状变化的影响，初步的定量分析表明，热内应力是γ’粗化的一个主要驱动力．