The stress-induced martensitic transformation and superelasticity in a βCu–Zn alloy containing α1 plates

The stress-induced martensitic transformation and superelasticity effect in a βCu–Zn alloy containing α₁ plates have been investigated. The results showed that the α₁ plates have no obvious effect on the deformation behavior in the aged specimens. The deformation behavior was dominated by the formation of stress-induced martensite (SIM). The cyclic loading–unloading behaviors and characteristics of the aged specimens were dependent on the test temperatures, which are similar to that of single-phase specimens. In addition, the mechanism of superelasticity in the alloy containing α₁ plates was not affected by the presence of the α₁ plates. The α₁ plates remain unchanged during stress cycling, which was independent of the test temperatures. The interface of SIM moved smoothly and was not hindered by the α₁ plates during the reversible martensitic transformation on loading–unloading cycle. Upon loading, the SIM cannot penetrate the α₁ plates ahead of them during their nucleation and growth, but may form the same variant on both sides of the α₁ plate at the same time or in sequence.     

Identification of the metastable phase α′m in a Zn/Al alloy containing Cu and Mg

Samples of the commercial pressure-diecast alloy ZA8 containing 8.1% Al, 1.1% Cu and 0.024% Mg have been examined by transmission electron microscopy (TEM). During decomposition of the high temperature f c c phase, on cooling after casting, a transitional phase was formed within the phase in both dendrites and eutectic. This phase was identified as the metastable phase _m containing 11% Al or 23% Al, with a f c c crystal structure and lattice parameter (at 11%) of about 0.394 nm. It had adopted a symmetrical cube/cube orientation relationship with the surrounding f c c phase. The stability of this metastable phase at ambient temperatures was greatly increased by the presence of copper.     

Zn离子注入GaP

为了研究结型发光材料的性能,进行了Zn离子注入到n型GaP中的试验。由于Zn离子对Ⅲ-Ⅴ族化合物半导体是P型掺杂物,因此,Zn离子注入到n型GaP晶体中,经真空退火可形成p-n结,在适当条件下即可发光。从而证实了Zn离子已经注入到了GaP晶体中。Zn离子的注入能量为180keV,注入剂量是1×1016cm-2；所用n型GaP是合成溶质扩散法(SSD)制成；注入样品的保护层使用高频溅射SiO2,膜厚9000A。注入后的退火是在真空度为10-5乇的石英管中进行,退火时间为30分钟和40分钟两种,退火温度为1000℃。退火后,用铁氰化钾配方对样品染色。金相显微镜测量结果为5μm,证明Zn离子注入后形成了p-n结。又用探针法使样品发光,光呈红色。对样品进行了光激发光的测量,光激是Ar 离子激发,波长在77k下4880A,测出了PL光谱,峰值波长为6648A和5760A。同样条件下,对纯高阻GaP材料经Zn离子注入后并不发光。对注入后的样品进行了背散射测量,使用1．5MeV的He 4离子入射,样品的面积为1mm2,用200道分析器检测,每道能量为8 keV,测得了样品的组分比,说明P的组分比Ga的组分多一些,所以样品的配比有待进一步改善。本试验指出：Zn注入GaP在上述条件下能形成发光的p-n结。还指出Za离子注入到GaP中,退火温度高于800℃时(如1000℃),只要保护层作得好,真空度足够高(10-5乇以上)对制成发光结是很有利的。     

Lignin-derived Zn single atom/N-codoped porous carbon for α-alkylation of aromatic ketones with alcohols via borrowing hydrogen strategy

A green and scalable strategy has been developed for the synthesis of lignin-derived Zn single atom/N-codoped porous carbon(LCN@Zn-SAC)containing similar ZnNx s...     

Zn的乡村大气腐蚀

在辽宁省乡村进行 Zn 的大气暴露试验,绘制乡村气氛中 Zn 的腐蚀图,并讨论大气环境因素对Zn 的腐蚀速率的影响。     

Formation Behavior of 14H Long Period Stacking Ordered Structure in Mg–Y–Zn Cast Alloys with Different α-Mg Fractions

Phase compositions and microstructure evolutions of three Mg–Y–Zn cast alloys during isothermal annealing at 773 K have been systematically investigated to clarify the formation behavior of 14 H long period stacking ordered(LPSO) structure from α-Mg grains.The annealed microstructure characteristics indicate that the 18 R phase is thermal stable in Mg86Y8Zn6 alloy where 18 R serves as matrix,and 14 H lamellar phase only forms within tiny α-Mg slices(less than 1% for volume fraction).The α-Mg grains in Mg88Y8Zn4 and Mg89Y8Zn3 alloys exhibit cellular shape,and 14 H phase forms and develops into lamellar shape in these cellular grains after annealing.The results suggest that the presence of α-Mg grains is a requirement for the generation of 14 H phase.The nucleation and growth rates of 14 H lamellas are accelerated in α-Mg grains with higher concentrations of stacking faults and solute atoms.Moreover,the 14 H lamellas are parallel to adjacent 18 R plates in Mg86Y8Zn6 alloy,but the 14 H phase precipitated in cellularα-Mg grains of Mg88Y8Zn4 and Mg89Y8Zn3 alloys exhibits random orientation relationship with surrounding 18 R phase,indicating that the orientation relationship between 14 H and 18 R phases depends on the relationship between α-Mg grains and 18 R phase.     

In vivo performances of pure Zn and Zn–Fe alloy as biodegradable implants

The disadvantage of current biodegradable metals such as Mg and Fe is the release of hydrogen gas in vivo that can cause gas embolism and the production of voluminous iron oxide that can cause inflammation, respectively. Such considerations have turned focus towards Zn as an alternative. This is based on the fact that Zn plays a crucial role in many physiological processes, as well as potentially being biocompatible and capable of with biodegradation. As such, the purpose of the present study was to evaluate the in vivo performance of pure Zinc and Zn–2%Fe implants. The use of iron as an alloying element was aimed at accelerating the corrosion rate of pure zinc by a micro-galvanic effect so as to maintain the post-implantation biodegradation characteristics of the implant. In vivo assessment was carried out using cylindrical disks implanted in the back midline of 16 male Wistar rats for up to 24 weeks. Post-implantation evaluation included monitoring the well-being of rats, weekly examination of hematological parameters: serum Zn levels, red and white blood cell counts and hemoglobin levels, X-ray radiography, histological analysis and corrosion rate assessment. The results obtained in terms of well-being, hematological tests and histological analysis of the rats indicate that the in vivo behavior of pure Zn and Zn–2%Fe implants was adequate and in line with the results obtained by the control group containing inert Ti–6Al–4V alloy implants. The corrosion rate of Zn–2%Fe alloy in in vivo conditions was relatively increased compared to pure Zn due to micro-galvanic corrosion.

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Microstructure control of α-Sialon ceramics by seeding with α-Sialon particles

A proper powder preparation was used to develop -Sialon single crystals as seeds. The microstructure and fracture toughness of seed-containing -Sialon ceramics sintered by hot-pressing were investigated. The specimen without seeding consisted of fine grains and a small amount of coarse grains. Specimens seeded with -Sialon single crystal particles presented a large amount of elongated -Sialon grains. The aspect ratio and the amount of elongated -Sialon grains can be tailored by using different sizes and amounts of the seeds. The fracture toughness of seed-containing -Sialon ceramics is improved, which is attributed to grain pullout and bridging of elongated grains.     

NaH_2PO_2对Zn、Zn－Fe合金电沉积的影响

用循环伏安法研究了ＮａＨ２ＰＯ２对Ｚｎ、Ｚｎ－Ｆｅ合金电沉积的影响，结果表明：镀液中加入ＮａＨ２ＰＯ２后，Ｚｎ、Ｚｎ－Ｆｅ合金电沉积的阴极极化增大；获得的Ｚｎ－Ｐ、Ｚｎ－Ｆｅ－Ｐ合金镀层的阳极溶解峰与Ｚｎ层相比，其峰电位正移。     

NaH2PO2对Zn,Zn—Fe合金电沉积的影响

用循环伏安法研究了ＮａＨ２ＯＰ２对Ｚｎ，Ｚｎ－Ｆｅ合金沉积的影响，结果表明，镀液中加入ＮａＨ２ＰＯ２后Ｚｎ，Ｚｎ－Ｆｅ合金电沉积的阴极极化增大，获得的Ｚｎ－Ｐ，Ｚｎ－Ｆｅ－Ｐ合金镀层的阳极溶解峰与Ｚｎ层相比，其峰电位正移。     

Zn—Al2O3和Zn—SiO2复合镀层的研制

详细叙述了Ｚｎ－Ａｌ２Ｏ３和Ｚｎ－ＳｉＯ２复合镀层的制做方法，提出了复合镀液中所用微粒子和净化处理方法。对复合镀层的耐腐蚀性和结合力进行了测定，得出了耐腐蚀性和结合力均较好的Ｚｎ－Ａｌ２Ｏ３和Ｚｎ－ＳｉＯ２复合镀层中粒子的含量范围等有用的数据。     

Zn－Al_2O_3和Zn－SiO_2复合镀层的研制

详细叙述了Ｚｎ－Ａｌ２Ｏ３和Ｚｎ－ＳｉＯ２复合镀层的制做方法，提出了复合镀液中所用微粒子和净化处理方法。对复合镀层的耐腐蚀性和结合力进行了测定，得出了耐腐蚀性和结合力均较好的Ｚｎ－Ａｌ２Ｏ３和Ｚｎ－ＳｉＯ２复合镀层中粒子的含量范围等有用的数据。     

InP材料Zn扩散的新方法

为了在InP材料中获得精确的浅结扩散和低的接触电阻,同时防止InP表面层分解,提出了一种以Zn膜作扩散源、用快速热处理工艺进行Zn扩散的新方法.实验结果表明,该方法不仅可以获得约5×1018cm-3的空穴浓度,而且扩散界面平坦、无尖峰.用SiNx/SiO2和Al2O3图形掩膜制备的p-n结二板管的反向击穿电压分别为28和37V,进一步验证了扩散界面良好的电学特性.