铝—锂合金中δ‘（Al3Li）沉淀相时效粗化行为及体积分数的测定

对经固溶处理的二种Ａｌ－Ｌｉ合金（１．９４ｗｔ．％Ｌｉ和２．７５ｗｔ．％Ｌｉ）的时效过程进行了研究。结果表明：δ＇的生长速率遵从Ｏｓｔｗａｒｄ粗化动力学。１．９４ｗｔ．％Ｌｉ合金δ＇产生于时效过程中，而２．７５ｗｔ．％Ｌｉ合金的δ＇产生于时效的前期阶段。前者的表观体积分数明显大于根据相图估算的数值，真实体积分数则与此值接近；后者的体积分数低于根据相图估算的数值，这可能归咎于δ＇固相线的位置、统计学     

Ni-Al二元镍基模型高温合金热暴露实验过程中γ′相尺寸与体积分数的变化

本文利用扫描电子显微镜（ SEM）,研究了Ni?Al二元模型镍基单晶高温合金在热暴露实验过程中γ′相尺寸与体积分数的变化。结果表明：随着热暴露时间的增加,一次γ′相尺寸明显增大,其长大机制为扩散控制的粗化机制（L?S?W理论）。其平均尺寸的立方与热暴露时间呈线性关系。通过对γ′相体积分数的统计显示,γ′相体积随热暴露时间的延长而减小,这是高温下γ相固溶度增加以及γ′溶解的结果,可以用Ni?Al二元相图来解释此现象。     

遥感仪器光机系统用高体分SiCp/Al复合材料的疲劳研究

由于高体分铝基复合材料应用在空间遥感器的结构设计中可能会存在疲劳问题,对高体分SiCp/Al复合材料的疲劳破坏行为进行了研究。首先,介绍了疲劳试验方法,确定采用常规 试验方法来研究高体分铝基复合材料的疲劳强度,并对疲劳试验进行了规划。然后通过用三参数幂函数模型处理实验数据获取了S-N曲线中关键参数的数学模型,提出了振动试验中的振动频率选取方法。最后利用振动试验台对5个疲劳试件进行了试验,并用三参数幂函数模型对观测值进行了拟合。结果表明,高体分SiCp/Al复合材料的疲劳强度为161 MPa。该研究结果能够有效地指导航天遥感器的结构设计工作。     

遥感仪器光机系统用高体分SiCp／A1复合材料的疲劳研究

由于高体分铝基复合材料应用在空间遥感器的结构设计中可能会存在疲劳问题，对高体分SiCp／A1复合材料的疲劳破坏行为进行了研究。首先，介绍了疲劳试验方法，确定采用常规试验方法来研究高体分铝基复合材料的疲劳强度，并对疲劳试验进行了规划。然后通过用三参数幂函数模型处理实验数据获取了SN曲线中关键参数的数学模型，提出了振动试验中的振动频率选取方法。最后利用振动试验台对5个疲劳试件进行了试验，并用三参数幂函数模型对观测值进行了拟合。结果表明，高体分SiCp／A1复合材料的疲劳强度为161MPa。该研究结果能够有效地指导航天遥感器的结     

Effects of Solder Volume on Formation and Redeposition of Au-Containing Intermetallics in Ni/Au-SnAgCu-Ni(P) Solder Joints

SnAgCu is one of the most promising candidates for lead-free solders to replace conventional eutectic SnPb solders. The effects of solder volume on interfacial reactions and microstructure evolution in Ni/Au-SnAgCu-Ni(P) solder joints have been investigated under soldering and thermal aging conditions. The results show that solder volume has a strong effect on the formation of Au-containing intermetallic compounds (IMCs) and their redeposition at the interfaces. The size and volume fraction of Au-containing IMCs dispersed in the solder bulk increased with decreasing solder joint dimensions. For the small solder joint with 300-μm solder ball, the (Au,Ni)Sn₄ IMCs redeposited to the interfaces after thermal aging at 150°C for 9 days, but this was not observed for the other two solder joints with large solder volume. These results also indicate that the redeposition of (Au,Ni)Sn₄ is closely associated with the migration of Cu toward the interfaces.     

Bi_(0.5)Na_(0.5)TiO_3-Ba(Al_(0.5)Sb_(0.5))O_3陶瓷的压电、铁电特性及场致应变效应

用普通陶瓷工艺制备了(1–x)Bi_(0.5)Na_(0.5)Ti O_3-x Ba(Al_(0.5)Sb_(0.5))O_3(x=0.03~0.05)压电陶瓷,研究了Ba(Al_(0.5)Sb_(0.5))O_3含量对Bi_(0.5)Na_(0.5)Ti O_3(BNT)压电陶瓷的介电、压电、铁电和场致应变效应的影响。研究表明,随着第二组元Ba(Al_(0.5)Sb_(0.5))O_3含量的增加,该陶瓷经历了从极性态的铁电相向非极性态的非铁电相的转变。在x=0.035组分处,多相共存导致样品具有最大的压电常数d_(33)=99 p C/N,最大的应变S_(max)=0.27%,机电耦合系数k_p=20.1%,k_t=30.4%,等效压电常数d~*_(33)=386 pm/V。     

Wetting Behavior of Ternary Au-Ge-X (X = Sb, Sn) Alloys on Cu and Ni

Au-Ge-based alloys are potential substitutes for Pb-rich solders currently used for high-temperature applications. In the present work, the wetting behavior of two Au-Ge-X (X = Sb, Sn) ternary alloys, i.e., Au-15Ge-17Sb and Au-13.7 Ge-15.3Sn (at.%), in contact with Cu and Ni substrates has been investigated. Au-13.7Ge-15.3Sn alloy showed complete wetting on both Cu and Ni substrates. Total spreading of Au-15Ge-17Sb alloy on Cu was also observed, while the final contact angle of this alloy on Ni was about 29°. Pronounced dissolution of Cu substrates into the solder alloys investigated was detected, while the formation of Ni-Ge intermetallic compounds at the interface of both solder/Ni systems suppressed the dissolution of Ni into the solder.     

(Na_(1/2)Bi_(1/2))TiO_3-SrTiO_3无铅压电陶瓷的介电、压电性能

研究了 (Na1 / 2 Bi1 / 2 ) Ti O3- Sr Ti O3二元系无铅压电陶瓷的介电、压电性性。Sr2 的引入对 NBT材料的常温介电系数、铁电相与反铁电相转变温度 TF A(180°C)以及居里温度 TC(30 0°C)的影响都不大 ,但却较大幅度地降低了 NBT材料的高矫顽场 ,从而使极化相对容易。(Na1 / 2 Bi1 / 2 ) Ti O3- Sr Ti O3二元系的压电性能参数 d33和 kt分别达到 10 0 p C/N和 0 .45     

NBT-Ba(NbO3)2无铅压电陶瓷的压电介电性能

采用传统陶瓷制备方法,制备了一种新的(Na1/2Bi1/2)TiO3基无铅压电陶瓷(1-x)(Na1/2Bi1/2)TiO3-xBa(NbO3)2(摩尔分数x=0~1.4%)。X-射线衍射分析表明,所研究的组成均能够形成纯钙钛矿(ABO3)型固溶体。SEM观察结果表明,掺入Ba(NbO3)2促进了长条状晶粒的析出。不同频率下陶瓷材料的介电常数-温度曲线显示该体系材料具有明显的弛豫铁电体特征,且随着Ba(NbO3)2的增加,其弛豫性特征愈明显。检测了不同组成陶瓷的压电性能,发现材料的压电常数d33和平面机电耦合系数kp随着x值的增加先增加后降低,在x=0.6%时,陶瓷的d33=94 pC/N,kp=0.171,为所研究组成中的最大值,介电损耗tanδ则随x值的增加而增加。     

Ga_(0.47)In_(0.53)As/SiO_2与Ga_(0.47)In_(0.53)As/Al_2O_3的界面性质

本文研究了GaInAs/SiO_2与GaInAs/Al_2O_3的界面性质.采用PECVD技术以TEOS为源以及采用MOCVD技术以Al(OC_3H_1)_3为源在n~+-InP衬底的n-Ga_(0.47) In_(0.33)As外延层上淀积了/SiO_2和Al_2O_3,制备成MIS结构.结果表明这些MIS结构具有良好的C-V特性,SiO_2/GaInAs界面在密度最低达 2.4×10~(11)cm~2·eV~(?),氧化物陷阱电荷密度达10~(?)～10~(10)cm~2,观察到GaInAs/SiO,结构中的深能级位置为E_c-E_T=0.39eV.GaInAs/Al_2O_3结构中的深能级位置为E_c=E_T=0.41eV.     

Dry etching of new phase-change material Al_(1.3)Sb_3Te in CF_4/Ar plasma

正The dry etching characteristic of Al_(1.3)Sb_3Te film was investigated by using a CF_4/Ar gas mixture.The experimental control parameters were gas flow rate into the chamber,CF_4/Ar ratio,the O_2 addition,the chamber background pressure,and the incident RF power applied to the lower electrode.The total flow rate was 50 sccm and the behavior of etch rate of Al_(1.3)Sb_3Te thin films was investigated as a function of the CF_4/Ar ratio,the O_2 addition,the chamber background pressure,and the incident RF power.Then the parameters were optimized.The fast etch rate was up to 70.8 nm/min and a smooth surface was achieved using optimized etching parameters of CF_4 concentration of 4%,power of 300 W and pressure of 80 mTorr.     

(Ca0.7Nd0.2)TiO3-(Li0.5Nd0.5)TiO3陶瓷的低温烧结与介电性能

用传统固相反应法合成(Ca0.7Nd0.2)TiO3-(Li0.5Nd0.5)TiO3(CLNT)陶瓷粉体.研究添加不同含量BaCu(B2O5)(BCB)对CLNT陶瓷的烧结特性及介电性能的影响.结果表明,其烧结温度降低了250℃,并且有第二相生成.当添加ω(BCB)=5%的CLNT陶瓷在950℃烧结2 h时,其介电性能为εr=94.03,tanδ=0.009 7,τf=1.076×10-6/℃,且介电损耗比纯片低.