铸轧辊温度场及热变形测定

针对铸轧工艺的特殊性，拟定了一套方便可行的铸轧辊温度场及热变形测试方案，运用该方案对某铸轧机成功地进行了工业现场测试，掌握了铸思辊在铸轧环境下温度场及热变形的分布规律，为铸轧板形控制及现场铸轧工艺优化提供了可靠依据。     

Microstructures and Properties of Laser-Glazed Plasma-Sprayed ZrO2-YO1.5/Ni-22Cr-10AI-1Y Thermal Barrier Coatings

Thermal barrier coatings (TBCs) consisting of two layers with various yttria contents (ZrO ₂- YO_1.5/Ni-22Cr-10Al- lY) were plasma sprayed, and parts of the various specimens were glazed by using a pulsed CO₂ laser. All the specimens were then subjected to furnace thermal cycling tests at 1100 °C; the effect of laser glazing on the durability and failure mechanism of the TBCs was then evaluated. From these results, two models were developed to show the failure mechanism of as- sprayed and laser- glazed TBCs: model A, which is thermal-stress dominant, and model V, which is oxidation-stress dominant. For top coats containing cubic phase, cubic and monoclinic phases, or tetragonal and a relatively larger amount of monoclinic phases, whose degradation is thermal- stress dominant, laser glazing improved the durability of TBCs by a factor of about two to six. Segmented cracks that occurred during glazing proved beneficial for accommodating thermal stress and raising the tolerance to oxidation, which resulted in a higher durability. Thermal barrier coatings with top coats containing tetragonal phase had the highest durability. Degradation of such TBCs resulted mainly from oxidation of the bond coats. For top coats with a greater amount of monoclinic phase, thermal mismatch stress occurred during cooling and detrimentally affected durability.     

321不锈钢点蚀电位影响因素的研究

通过正交设计和对比实验研究了温度、pH值以及Cl-和SO2-4含量对321不锈钢点蚀电位的影响.正交设计表明,温度和Cl-(Cl-≥0.014mol/L)含量对点蚀电位Eb的影响显著,但pH值(6～9)则没有影响.对比实验表明,当Cl-≤0.014 mol/L时,Cl-对Eb没有影响,当Cl-＞0.014 mol/L,则Eb随Cl-浓度对数升高而线性下降.点蚀电位随温度升高而下降.如不含Cl-,则SO2-4对Eb没有影响,当Cl-=0.028 mol/L时,Eb随SO2-4浓度升高而升高,并趋于稳定值.     

SIMA法制备LC4半固态合金的流变行为研究

半固态坯的流动性能是获得优质、复杂制件的基础和关键。通过对两种状态合金在相同载荷作用下进行半固态压缩试验,结果表明:挤压态合金的流动性最差,挤压后冷变形态合金Ⅱ(压缩方向垂直于冷变形方向)的流动性最好。这主要有两方面的原因:一是晶粒形状上的差异;二是与半固态坯料的制备历史及其后续加工有关。     

Surface destructive mechanism on high-temperature ablation, supersonic-erosion, dreg-adherence and corrosion

The exhaust and flame from a supersonic airborne missile high-energy smoke-born engine (SAMHSE) may lead to high-temperature ablation, supersonic-erosion, dreg-adherence (HTASED) and corrosion on the launcher slide track, causing serious problems to the operation and decreasing the lifetime of the launcher. Therefore, it is imperative to study the destructive mechanism so as to guarantee the smooth operation and increase the lifetime of military equipments. Accordingly, HTASED and corrosion were systematically observed and analyzed with the emphasis placed on the mechanism investigations making use of a series evaluation tests, typical missile engine simulation tests, national military standard methods, scanning electron microscopy and electrochemical corrosion tests. It is found that the thermal impact of high-temperature flame and supersonic erosion of corrosive melting particle jet of the SAMHSE lead to surface defects of micro-cracks, denudation and corrosive residue. Some defects reach to metal base becoming to "corrosive channels". Repetitive HTASED may cause ablation-adhesion fatigue stress, which enhances the surface corrosion and destruction. HTASED and corrosion are related to the type of a SAMHSE fuel and experience of the launcher. Surface destruction is related to synergistic effects of the HTASED. The ablated and failed Al or steel surface is liable to electrochemical corrosion characterized by pitting in humid and salt-spray environment.     

嵌入式电子节温器综合检测系统设计北大核心

设计一款基于嵌入式系统的汽车电子节温器综合检测系统,采用空气作为泄漏测试介质,效率和安全性相比使用PLC和水介质的传统检测系统高。系统由上位机与下位机组成:下位机使用STM32F405RGT6处理器;上位机基于LabVIEW软件开发。系统能够完成包括汽车电子节温器内泄漏测试、外泄漏测试和流量测试,能够实时采集电机工作电压、电流、温度,完成电机位置与角度传感器标定,并生成数据报表和曲线,最终可以判定电子节温器样件合格与否。     

弧焊电源智能化测试、分析与评价平台

弧焊电源智能化测试平台的研制开发具有重要的意义。该测试平台由硬件平台和软件平台2部分构成。硬件平台为计算机控制下的大功率电阻负载及数据采集系统，软件平台为运行在Windows 2000环境下的模块化数据测试与分析软件。该测试平台可以实现对弧焊电源外特性、调节特性和动特性的自动测试，同时具有对测试数据进行分析和抽提取并据此对弧焊电源的性能进行评价和初步诊断的功能。     

铜－钢电偶加速钢在土壤中腐蚀的研究──大庆土壤试验的部分结果

铜－钢电偶对在土壤中可以加速钢的腐蚀，在大庆土中，当铜－钢电偶的面积比达３０：１时，控制一定的温度、湿度条件，可以使钢的腐蚀在半年内达到或超过现场埋片３０ａ的程度，因此有可能用短期的室内电偶腐蚀加速试验数据来预测现场埋片长期的腐蚀程度．     

Q235钢静载拉伸过程中的磁记忆信号变化特征分析

选取Q235钢进行静载拉伸试验，利用EMS2003型磁记忆检测系统进行各级应力水平的检测。结果显示弹性极限范围内磁场强度曲线形貌接近未加载时，进入屈服阶段后磁场强度值明显增加，过零点数目在静载拉伸过程中呈现无规律变化，但弹塑性加载阶段均出现了过零点逼近最终断裂处的现象。该试验表明进入塑变后材料的组织结构变化与其所表现出的表面磁场强度值之间必然存在着某种对应关系，为磁记忆检测的进一步研究奠定了基础。     

数据采集与变频调速在插销裂纹试验机上的应用

针对插销裂纹试验机加裁过程波动大，影响试验结果的问题，利用数据采集技术记录插销所经历的热循环和裁荷历程，通过采集卡的数字输出通道控制继电器的通断，从而改变变频器的输出电压相位，达到控制插销试验机电机转向的目的；对于试验过程中给定的载荷设定值，系统根据等比关系将其模糊化成几个区间，并确定当前采集到的载荷的所在区间，根据区间的不同，赋予采集卡的模拟输出通道一变化电压值，将其输出到变频器，最终控制电动机的转速。试验结果表明，加载过程实现了自动化和平稳化，并且在栽荷设定值处没有超调量。