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Wang Q.-D.,Shanghai JiaoTong University | Gao Y.,Shanghai JiaoTong University | Gao Y.,Grikin Advanced Materials Co. | Yin D.-D.,Shanghai JiaoTong University | Chen C.-J.,Shanghai JiaoTong University
Transactions of Nonferrous Metals Society of China (English Edition) | Year: 2010

Characterizations of phases in Mg-10Y-5Gd-2Zn-0.5Zr (WGZ1052) alloy during heat treatments were investigated by OM, XRD, SEM and EDS. The mechanisms of microstructure evolution were discussed. The results show that, after high temperature heat treatments, the Mg12ZnY phases still exist. During solution-treatment at 535 °C, the amount of the long-period stacking order structures decreases. At 545 °C for 20 h and 24 h, there are still remnant Mg12ZnY compounds in the Mg matrix, the shape of which does not change and the amount does not decrease obviously. © 2010 The Nonferrous Metals Society of China.

Gu X.,Tsinghua University | Gu X.,Grikin Advanced Materials Co. | Zhang W.,Tsinghua University
Science China Technological Sciences | Year: 2012

The O-line model is usually applied to precipitation crystallography. Its application to investigation of martensite crystallography has received little attention. In this paper, the relationship between O-line model and the prism matching model for martensite crystallography is established. The formulas in the O-line model are applicable to martensite crystallography. Analytical solution of the habit plane corresponding to the minimum shape strain has been derived. A calculation example of {3 10 15} f martensite in a ferrous alloy is provided. While the results are in agreement with the former models for martensite crystallography, the advantage of O-line model is that it offers analytical solutions, facilitating further systematic investigations. © 2011 Science China Press and Springer-Verlag Berlin Heidelberg.

Wang Z.,Grikin Advanced Materials Co. | Wang Z.,Chongqing University of Technology | Huang W.,Chongqing University of Technology | Ma Y.,Chongqing University of Technology
Materials Science and Engineering C | Year: 2014

The micro-scale abrasion behaviors of surgical implant materials have often been reported in the literature. However, little work has been reported on the micro-scale abrasive wear behavior of Ti-25Nb-3Mo-3Zr-2Sn (TLM) titanium alloy in simulated body fluids, especially with respect to friction pairs. Therefore, a TE66 Micro-Scale Abrasion Tester was used to study the micro-scale abrasive wear behavior of the TLM alloy. This study covers the friction coefficient and wear loss of the TLM alloy induced by various friction pairs. Different friction pairs comprised of ZrO2, Si3N4 and Al 2O3 ceramic balls with 25.4 mm diameters were employed. The micro-scale abrasive wear mechanisms and synergistic effect between corrosion and micro-abrasion of the TLM alloy were investigated under various wear-corrosion conditions employing an abrasive, comprised of SiC (3.5 ± 0.5 μm), in two test solutions, Hanks' solution and distilled water. Before the test, the specimens were heat treated at 760 °C/1.0/AC + 550°C/6.0/AC. It was discovered that the friction coefficient values of the TLM alloy are larger than those in distilled water regardless of friction pairs used, because of the corrosive Hanks' solution. It was also found that the value of the friction coefficient was volatile at the beginning of wear testing, and it became more stable with further experiments. Because the ceramic balls have different properties, especially with respect to the Vickers hardness (Hv), the wear loss of the TLM alloy increased as the ball hardness increased. In addition, the wear loss of the TLM alloy in Hanks' solution was greater than that in distilled water, and this was due to the synergistic effect of micro-abrasion and corrosion, and this micro-abrasion played a leading role in the wear process. The micro-scale abrasive wear mechanism of the TLM alloy gradually changed from two-body to mixed abrasion and then to three-body abrasion as the Vickers hardness of the balls increased. © 2014 Elsevier B.V.

PubMed | Beijing University of Technology, China University of Petroleum - Beijing, University of Western Australia and GRIKIN Advanced Materials Co.
Type: | Journal: Scientific reports | Year: 2015

Freestanding nanowires have been found to exhibit ultra-large elastic strains (4 to 7%) and ultra-high strengths, but exploiting their intrinsic superior mechanical properties in bulk forms has proven to be difficult. A recent study has demonstrated that ultra-large elastic strains of ~6% can be achieved in Nb nanowires embedded in a NiTi matrix, on the principle of lattice strain matching. To verify this hypothesis, this study investigated the elastic deformation behavior of a Nb nanowire embedded in NiTi matrix by means of in situ transmission electron microscopic measurement during tensile deformation. The experimental work revealed that ultra-large local elastic lattice strains of up to 8% are induced in the Nb nanowire in regions adjacent to stress-induced martensite domains in the NiTi matrix, whilst other parts of the nanowires exhibit much reduced lattice strains when adjacent to the untransformed austenite in the NiTi matrix. These observations provide a direct evidence of the proposed mechanism of lattice strain matching, thus a novel approach to designing nanocomposites of superior mechanical properties.

Li J.,GRIKIN Advanced Materials Co. | Zheng Y.,China University of Petroleum - Beijing | Cui L.,China University of Petroleum - Beijing
Journal of Materials Engineering and Performance | Year: 2010

Incomplete martensitic transformation characteristics of NiTi shape memory alloys after cold deformation were studied. By designing the shape of the original surface curve, macroscopic domains with different dislocation density were introduced into the NiTi alloys and materials possessing the characteristics of composites were obtained. Due to the interactions between the dislocation texture and martensite variants, the reverse transformation temperatures were found to expand over a large temperature window, which gives temperature memory effect a higher potential for application. © ASM International.

Xu G.J.,Grikin Advanced Materials Co. | Luo J.F.,Grikin Advanced Materials Co. | Li Y.J.,Grikin Advanced Materials Co. | He J.J.,Grikin Advanced Materials Co. | And 2 more authors.
Materials Science Forum | Year: 2016

Pass through flux (PTF) is an essential parameter for the magnetron sputtering process of ferromagnetic materials. In the present investigation the influence of deformation, recrystallized microstructure and thickness on PTF of Ni was examined by the analysis of microstructure and hardness of high purity Ni. The experimental results showed that PTF of rolled Ni increased significantly comparing to the annealing microstructure that is related to the dislocation and stress of microstructure. With the recrystallization and grain growth of deformed samples, PTF decreased to be about 30%. PTF was also associated with the thickness of material. It increased by 6% when the thickness of 0.5mm decreased. This research is useful to guide and improve the design, development and preparation of magnetic sputtering materials. © 2016 Trans Tech Publications, Switzerland.

He J.,GRIKIN Advanced Materials Company Ltd | Xu X.,GRIKIN Advanced Materials Company Ltd | Wang Y.,GRIKIN Advanced Materials Company Ltd | Li Y.,GRIKIN Advanced Materials Company Ltd
Hanjie Xuebao/Transactions of the China Welding Institution | Year: 2015

Soldering titanium and copper using Ni/Al self-propagating multilayer foil as thermal source instead of traditional heater. Flatness, soldering ratio, shearing strength and the interface of Ni/Al self-propagating multilayer foil and solder were evaluated. There was little difference before and after soldering of the assembly temperature. The weld assembly achieved flatness within 0.1 mm, soldering ratio was 98.3% and shearing strength was 40.791 MPa. SEM analysis showed that there was a close joint between Ni/Al foil and solder. Residual stress in joint was reduced with the deintegarion of Ni/Al foil and solder flowed through the fissure. ©, 2015, Harbin Research Institute of Welding. All right reserved.

Wang Z.,Grikin Advanced Materials Co. | Wang Z.,General Research Institute for Nonferrous Metals, China | Cai H.,Grikin Advanced Materials Co. | Hui S.,General Research Institute for Nonferrous Metals, China
Journal of Alloys and Compounds | Year: 2015

The relationship between microstructure and mechanical properties of a novel Ti-3.0Al-3.7Cr-2.0Fe alloy were studied. The effects of cooling rates and solution temperature were considered. The analysis methods of optical microscope (OM), X-ray diffractometer (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM) were used. The results indicate that β and α phase in this alloy are obtained after solution treated at 1183 K on the cooling ways of air cooling and furnace cooling; and β and α″ martensite are observed after quenching in water. Besides, the volume of α phase is decreased with increasing solution temperature. In the present study, the ultimate strength 1065 MPa with 12.0% in elongation of the alloy is acquired under the heat treatment condition of 1183 K/30 min/AC, and the strength-ductility combination in this case is also the best. Under the heat treatment condition of 1183 K/30 min/WQ, the elasticity modulus of the alloy is only 91.3 GPa, as a result of the lower elasticity modulus of β phase. © 2015 Elsevier B.V. All rights reserved.

Kong F.,University of Science and Technology Beijing | Kong F.,Grikin Advanced Materials Co. | Zhang X.,Harvard University | Hai M.,University of Science and Technology Beijing | Hai M.,Harvard University
Langmuir | Year: 2014

We encapsulate the hydrophilic anti-cancer drug doxurubicin hydrochloride (DOX) with about 94% drug encapsulation efficiency, either alone or with nanomagnetite, in monodisperse biocompatible phospholipid vesicles. Glass capillary microfluidics is used to generate monodisperse water in oil in water (w/o/w) double-emulsion templates with a core-shell structure by using a mixture of liquid unsaturated phospholipids and powdered saturated phospholipid. This combination would overcome the low transition temperature of unsaturated powdered phospholipid and the solubility limitation of saturated phospholipid, as well as improving the fabrication of stable monodisperse phospholipid vesicles. The double-emulsion droplet is controlled from 50 to 200 μm according to different flow rates, and the final phospholipid vesicles are retained after a solvent removal step by dewetting. DOX-loaded phospholipid vesicles show sustained release compared with free DOX water solution. The in vitro cell viability of 100 μg/mL phospholipid vesicles on HeLa or MCF-7 cells after 24 h incubation at 310 K is above 90%, confirming the excellent biocompatibility of the phospholipid vesicles. These biocompatible phospholipid vesicles are promising oral drug delivery vehicles for biomedical applications and magnetic resonance imaging contrast agents for biomedical diagnosis. © 2014 American Chemical Society.

Feng Z.-W.,Grikin Advanced Materials Co. | Mi X.-J.,General Research Institute for Nonferrous Metals, China | Wang J.-B.,Grikin Advanced Materials Co. | Yuan Z.-S.,Grikin Advanced Materials Co. | And 2 more authors.
Zhongguo Youse Jinshu Xuebao/Chinese Journal of Nonferrous Metals | Year: 2013

The effects of the cold rolling reduction and annealing temperature on the texture and properties of Ni47Ti44Nb9 first and secondary cold-rolled plate were investigated by using XRD method. The results show that the major texture of the first cold-rolled plate is {111}<110> that is different from the hot-rolled texture and the orientation density increases slightly with increase of cold reduction when the cold reduction is less than 35%. The orientation density of the secondary cold-rolled plate is greatly enhanced and the major texture is {111}<110> and spreads from {111}<110> to {110}<110> in a <110>//RD fiber. When the annealing temperature of the secondary cold-rolled plate is above 500 °C the major texture is {111}<112> recrystallization texture. The orientation density is obviously higher in the secondary cold-rolled plate after furnace cooling at 700 °C for 60 min than that of water quenching texture.

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