RESEARCH ON REFRACTORY SUPERALLOYS IN THE HTM 21 PROJECT

It was proposed that a new class of alloys based on platinum group metals (PGMs) were calle drefractory superalloys. These refractory superalloys have an fcc and L12 coherent two-phase structure (similar to that of Ni-based superalloys), high melting temperatures and good potential as structural materials used at temperatures up to 1800℃. Our recent results on the microstructure evolution, deformation and fracture behavior of some of these refracotry superaUoys, especial lr- and Rh-base refractory superalloys were reported.     

Impurity-controlled Mo films as diffusion barriers for Cu metallization

Effects of vacuum conditions on the oxygen content and microstructure of Mo layers used with Cu gate lines as thin-film transistor-liquid crystal display diffusion barriers were investigated. Mo was deposited using ion-beam sputtering at 1.0 × 10^?5 and 7.0 × 10^?7 Torr. The Mo layer oxygen content and the microstructure and changes in chemical composition of the Cu/Mo/SiO₂/Si layer during annealing were examined. The Mo layer microstructure was influenced by oxygen; increasing concentration increased the energy required for secondary grain growth. Growth was suppressed at high oxygen levels. Therefore, diffusion barrier performance is enhanced by finer Mo layer grain sizes.     

固溶处理对A286合金组织与硬度的影响

通过光学显微镜、扫描电镜和洛氏硬度计等研究了固溶温度(980、1000、1020℃)和保温时间(60、90、120 min)对A286合金微观组织和硬度的影响。结果表明,热轧态合金基体为再结晶的均匀奥氏体晶粒组织,同时存在一次碳氮化物。随着固溶温度的升高和保温时间的延长,再结晶晶粒优先从表面生长并逐渐向内部扩展,晶界有较大尺寸磷化物析出,合金硬度小幅度降低。     

激光重熔处理对铝合金微弧氧化层组织及性能的影响

采用激光重熔处理改善6061铝合金微弧氧化层的耐蚀性,采用光学显微镜、共聚焦显微镜、扫描电镜、X射线衍射仪、电化学工作站等研究了500～1000 W激光功率下微弧氧化层孔隙率、粗糙度、表面形貌、物相组成及耐蚀性能。结果表明,经过激光重熔处理后微弧氧化层主要由α-Al₂O₃和γ-Al₂O₃两相组成,随着激光功率的增加,γ-Al₂O₃向α-Al₂O₃转化的程度增加。激光功率为500～900 W时微弧氧化层孔隙率先增加后减小,但粗糙度变化不明显;1000 W时微弧氧化层鼓起、开裂,粗糙度、孔隙率增加。激光功率为900 W时微弧氧化层表面微孔孔径减小甚至闭合、裂纹数量减少,孔隙率降至最低,耐蚀性能最好。     

喷雾干燥结合等离子球化法制备NbMoTaWZr-HfC粉末的特性与组织演变研究

采用喷雾干燥+射频等离子体球化法制备NbMoTaWZr-HfC球形粉末,并对粉末的宏观特性、物相组成和微观组织形貌进行研究和分析。结果表明,制备的复合粉末形状为球形,粒度范围为13.31～32.11μm,D50=19.62μm。粉末球形度、流速和松装密度分别为0.98、0.198 s/g,7.20 g/cm³。球化后粉末由体心立方(bcc)固溶体+ZrO₂+HfC物相组成,其内部组织为枝晶和胞状晶混合组织。球化后粉末颗粒整体成分均匀,但在枝晶微区存在元素偏析,其中W、Mo、Ta等高熔点元素在枝晶臂富集,Nb、Zr等低熔点元素在枝晶间富集,而Hf元素分布均匀。     

Effect of HEA/Al composite interlayer on microstructure and mechanical property of Ti/Mg bimetal composite by solid-liquid compound casting

In this study,HEA/AI composite interlayer was used to fabricate Ti/Mg bimetal composites by solidliquid compound casting process.The Al layer was prepared on the surface of TC4 alloy by hot dipping,and the FeCoNiCr HEA layer was prepared by magnetron sputtering onto the Al layer.The influence of the HEA layer thickness and pouring temperature on interface evolution was investigated based on SEM observation and thermodynamic analysis.Results indicate that the sluggish diffusion effect of HEA can ...     

新型混粉电火花镜面加工实验装置的研制

针对混粉电火花加工的实验装置成本高、电蚀产物分离难等问题,利用水力旋流器超细分级分离的特性,设计了可在线过滤混粉电火花加工工作液的新型实验装置,同时设计了新型的储液箱搅拌系统和工作液体槽内的搅拌装置,能很好地保证混粉电火花加工过程中粉末浓度的均匀性.该实验装置的研制为将来实现混粉、常规电火花加工工作液箱一体化的电火花成形机提供了可行性验证.     

Pb(Mg_(1+x)/3Nb_(2-x)/3)O_3铁电材料中有序-无序相变的理论研究

基于Kikuchi自洽迭代方法,利用有序-无序相变理论,并取最近邻相互作用近似,研究了Pb(Mg_((1+x)/2)Nb_((2-x)/2)O_3晶粒中在x=0.5时有序区形成的原因,提出Mg~(2+)∶Nb~(5+)=1∶1(离子数比)时,形成B位有序排列最为有利,并且弱的空间电荷场不影响这种有序排列的形成,同时给出了温度-组份的有序-无序相图。     

SPS及其镧离聚物对PS/PBMA共混体系相容性的影响

通过运用溶液成膜共混法制备了系列聚苯乙烯／聚人烯酸丁酯（ＰＳ／ＰＢＭＡ）共混物。借助差示扫描量热法（ＤＳＣ）、傅里叶变换红外光谱（ＦＴＩＲ）、扫描电子显微镜９ＳＥＭ）研究了磺化磺苯乙烯（ＳＰＳ）及其离物对共体系相容性的影响。共混物中ＳＰＳ磺化度越高,ＰＢＭＡ相的下班伦为温度向高温方向移动越明显 。ＳＰＳ镧离聚物（ＳＰＳ１．８－Ｌａ）为增容剂时,ＤＣＳ结果显示共混物２相Ｔｇ靠扰;ＳＥＭ归咎显示２相分     

对称型双端过渡态异戊二烯/苯乙烯嵌段共聚物的相转变行为

以双卤代烷烃取代型双锂齐聚物为引发剂、环已烷为溶剂,异戊二烯（Ｉ）、苯乙烯（Ｓ）单体采用１次加入的方法,合成了对称型双端过渡态异戊二烯／苯乙烯嵌段共聚物Ｓ－（Ｓ／Ｉ）－Ｉ－（Ｉ／Ｓ）－Ｓ,并对新型嵌段共聚物的相转变行为进行了研究,在国内外首次检测到苒段共聚物的玻璃化转变温度（Ｔｇ）,证明过渡态异戊二烯、苯乙烯共聚物苒段的Ｔｇ的存在。