微重力偏晶合金凝固特征SCIEI

对在微重力条件下获取的Al-In(95wt-%)偏晶合金的显微组织特征进行了分析,结果表明,在空间制取的试样的Al枝晶中,还存在着大量的In质点;并且这些质点的分布具有某种规律性,由此形成了与地基样品显微组织上的明显差异,反映出一种与重力效应相关的材料凝固特性。     

高强度耐候钢焊接性分析与研究

通过对高强度耐候钢焊接性分析，采用与之匹配的焊接材料，对高强度耐候钢与不同钢种间焊接接头进行低温抗裂性、力学性能、耐大气腐蚀性能和焊接工艺性等进行试验，并对焊接接头金相组织进行分析，提出了高强度耐候钢焊接工艺及适宜的焊接材料。     

车轮的热烈和磨损机理与抗热裂耐磨车轮的研制

本文研究了车轮踏面的热裂和磨损机理,结果表明,车轮热裂主要与其含碳量和硬度有关;在使用合成闸瓦时,车轮踏面的磨损率与新形成的“白层”(马氏体)的断裂韧性有关。研制的抗热裂耐磨车轮(55SiMn)取得了明显的运用效果。     

AGING BEHAVIOUR OF PARTICULATE REINFORCED ALUMINUM ALLOY MATRIX COMPOSITES

The process of aging precipitation in SiC_p/6061 and Al_2O_3/6061 composites were investigated. Hardness testing, differential scanning calorimetry(DSC) and transmission electron microscopy were employed. Results showed that the precipitation phase form directly along dislocation lines in the composites because the particles produce high densities of dislocations which makes vacancy densities in the composites decrease, and the main precipitation phase at peak hardness was β′ phase.     

Cu—Zn—Al合金贝氏体的初生态及三维台阶

利用透射电镜研究了Cu—25.9Zn—3.75Al(wt-%)合金的贝氏体相变机制结果表明,贝氏体α_1在形成初期内部没有层错,早期典型形态为一侧比较平直,另一侧则存在三维巨型台阶,台阶宽面与贝氏体惯习面平行,其高度和间距分别约为10—40和50—230nm,台阶是可动的,贝氏体通过台阶的移动而增厚     

FeMoAl COATING AND ITS HIGHTEMPERATURE SULFIDATION PROPERTIES

ＦｅＭｏＡｌＣＯＡＴＩＮＧＡＮＤＩＴＳＨＩＧＨＴＥＭＰＥＲＡＴＵＲＥＳＵＬＦＩＤＡＴＩＯＮＰＲＯＰＥＲＴＩＥＳ①ＬｉＦａｎｇ，ＨｅＹｅｄｏｎｇ，ＱｉＨｕｉｂｉｎ，ＨｕａｎｇＺｈｅｎｚｈｏｎｇ，ＺｈｕＲｉｚｈａｎｇＢｅｉｊｉｎｇＣｏｒｏｓｉｏｎａｎｄ...     

SLOW PROPAGATION OF FATIGUE CRACK NEAR THRESHOLD

The effect of pearlite interlamellar spacing(d)from 0.31 to 0.77 μm of T8 steel on fatiguecrack propagation near threshold has been investigated at different stress ratios(R).Theclosure stress intensity factor(K_(cl)),the threshold value(ΔK_(th))and crack tip opening dis-placement range(ΔCOD)were measured.The results show that pearlite interlamellar spac-ing in this range has no effect on K_(cl),but has effect on the threshold value in low stress ratio.The threshold value is higher for materials with larger interlamellar spacing.No matter whatthe stress ratio is,during the propagation near threshold,the propagation rate will be thesame,provieded the crack tip opening displacement range is the same.Metallurgical examinations were also carried out to show that the crack propagationpath is sensitive to mierostructure.The crack always propagates along either boundary ofpearlite colony or ferrite lamellar in pearlite.     

Study of modeling and simulation of full digital controlled PMIG／MAG welding system based on Matlab／Simulink

This paper presents an integrated simulation model for full digital controlled PMIG/MAG welding system with Matlab/Simulink, and it consists of power inverter, digital control system and dynamic arc-load model. An integrated simulation study was done for fuU digital PMIG/MAG welding, and a method of connecting dynamic arc-load model to the system with controlled current source was presented, in addition, the simulation results were utilized to study the issues of digital control PMIG/MAG welding in this paper. The experimental results validated the developed simulation model, and this simulation study can be applied in implementation of the full digital PMIG/MAG welding and analysis of system dynamic process.     

SOME THERMODYNAMIC PROPERTIES IN PROCESS OF THERMAL REDUCTION OF Mg WITH HIGH AI ALLOY

本文以含高Al(Al76％,Si18.9％,Fe5.1％)的Al-Si-Fe合金为还原剂,在不同温度下进行热法还原Mg实验,测定了Mg的蒸气压为lgp_(Mg)=-8853/T+10.58.与用Si-Fe还原剂相比,在相同的p_(Mg)下,还原温度可下降约200℃。 用Bonnier法和本实验所测定的数据计算了Al-Si-Fe合金在不同温度下各组元的活度。结果表明,三元系中各组元活度均有负偏差,尤其Fe的偏差很大。另外,由以上所得的活度数据还计算了还原反应的平衡常数和热焓,分别为: lgK_[Al]=-18.40×10~4/T+117.2,ΔH=3529.5KJ     

水陆装甲车车体锈层分析

采用x射线衍射、SEM和EPMA等方法对服役20年～30年 水陆装甲车车体锈层进行了研究，研究表明：锈层中含有Cl-，锈层主要由α-FeOOH、β-FeOOH、γ-FeOOH、γ-Fe2O3、Fe3O4以及α-Fe等相组成，同时还残留有极少量的绿锈GR*(I).结合水陆装甲车的使用环境(海水、淡水，干湿交替)，对锈层各相的成因进行了分析.内锈层致密，大蚀坑下有小蚀坑，锈层中包含有呈小岛状弥散分布的Fe基体，均匀腐蚀与局部点蚀共同造成了材料的腐蚀破坏.