a—TCP／TTCP牙根管充填材料

a－TCP／TTCP骨水泥具有良好的水化硬化特性，符合临床需要的凝结时间和抗压强度，其水化产物主要为羟基磷灰石（HAP），以a－TCP／TTCP骨水泥作为牙根管充填材料，通过体外实验、动物实验，结合组织形态学及扫描电镜观察，检测a－TCP／TTCP牙根管充填材料的组织相容性，并动态观察根尖闭合情况及根尖周组织修复过程。结果表明，材料优良的生物相容性，在牙根管内可继续水化硬化，而且能引导根尖钙化组织沉积，封闭根尖孔，形成骨性结合，并促进根尖周组织愈合。     

α -TCP/TTCP牙根管充填材料

α TCP/TTCP骨水泥具有良好的水化硬化特性 ,符合临床需要的凝结时间和抗压强度 ,其水化产物主要为羟基磷灰石 (HAP)。以α TCP/TTCP骨水泥作为牙根管充填材料 ,通过体外实验、动物实验 ,结合组织形态学及扫描电镜观察 ,检测α TCP/TTCP牙根管充填材料的组织相容性 ,并动态观察根尖闭合情况及根尖周组织修复过程。结果表明 ,材料具有优良的生物相容性 ,在牙根管内可继续水化硬化 ,而且能引导根尖钙化组织沉积 ,封闭根尖孔 ,形成骨性结合 ,并促进根尖周组织愈合     

多巴胺载入对磷酸钙骨水泥性能的影响及体外生物学评价

本实验利用具有良好生物相容性和强黏附性能的多巴胺(dopamine,DA)提高磷酸钙骨水泥(calcium phosphate cement,CPC)的抗压强度,采用X射线衍射仪、X射线光电子能谱仪、万能材料力学试验机和场发射扫描电镜研究载多巴胺磷酸钙骨水泥(DA-CPC)的理化性能;将DA-CPC与成骨细胞(MC3T3-E1)体外共培养,以荧光显微镜观察细胞形貌,并进行Alamar Blue和碱性磷酸酶检测,研究DA载入后对成骨细胞增殖和分化的影响。结果表明:DA载入CPC中可发生自聚合形成聚多巴胺,促进CPC中的α-TCP和DCPD的溶解与转化,并不改变最终水化相成分;显著地提高CPC的抗压强度;DA的载入有利于成骨细胞的早期粘附和增殖,并不影响其分化。本实验表明载入DA的CPC具有良好的生物相容性,载入DA为提高CPC的抗压强度提供了一条可能的途径。     

HA／β-TCP双相磷酸钙陶瓷材料的生物学性能研究

研究了双相磷酸钙陶瓷在SBF中类骨磷灰石的形成，采用小鼠骨骼肌母细胞C2C12细胞系和HA／β-TCP复合培养，通过细胞增殖实验，电镜和荧光染色法观察并实施动物肌肉内植入实验，得出：材料在SBF中浸泡后有利于类骨磷灰石的沉积。细胞在HA／β-TCP支架材料上生长良好。对HA／β-TCP进行细胞毒性评价，与阴性对照组比较，样品不抑制细胞增殖，表现出良好的生物相容性。HA／β-TCP支架材料能促进细胞的增殖。动物实验表明，在体内HA／β-TCP有很好的骨形成能力。因此，实验制备的HA／β-TCP支架材料有良好的生物学性能。     

PHBV微球／磷酸钙骨水泥复合材料研究

采用在磷酸钙骨水泥中添加一定量的PHBV微球来制备在初期有较高的抗压强度，而后随着PHBV微球的降解，在磷酸钙骨水泥基体中形成三维孔隙结构的PHBV微球／磷酸钙骨水泥复合材料。选用的骨水泥的固相成分以α-TCP为主，液相成分为NaH2PO4／Na2HPO4、KH2PO4/K2HPO4缓冲溶液，PHBV微球直径为100μm～300μm，主要研究不同的固化液，固液比以及PHBV微球添加量对PHBV／磷酸钙骨水泥复合材料抗压强度等性能的影响，制备出凝固时间在15min-30min，具备一定可注射性，抗压强度达到10MPa～30MPa的PHBV微球／磷酸钙骨水泥复合材料。最终制备的PHBV微球／磷酸钙骨水泥复合材料能够满足骨修复材料的要求。     

壳聚糖微球/磷酸钙骨水泥复合材料动物体内植入实验研究

将壳聚糖微球/磷酸钙骨水泥复合材料植入兔股骨髁内,进行大体观察和X光片观察,并分别在植入兔股骨髁内8、16和24周,取出样本进行组织学观察和环境扫描电镜观察,研究植入材料与骨组织界面的结合状况和材料在动物体内的降解过程及新骨重建生成状况,探索材料在体内的降解机制和成骨机制.结果表明:壳聚糖微球/磷酸钙骨水泥在骨组织内具有良好的生物相容、组织相容性和和骨结合性,能够与自然骨组织形成紧密的骨性结合.材料在体内具有较快的降解速度,植入24周后,80%以上材料降解,被新生骨组织替代,该材料还具有良好的可塑性和临床操作性,是一种很有临床应用前景的骨修复材料.     

组织工程化三维仿骨支架重建股骨头坏死区研究

首先研制出具有取向性类骨结构的β-TCP三维仿骨支架,经过仿生类骨处理和组织工程化后,植入犬的股骨头坏死区,30周后取出股骨头进行分析研究.与此同时开展了几种支架材料重建股骨头坏死区的力学性能分析和模拟.结果显示,具有取向性类骨结构的β-TCP三维仿骨支架具有很好的生物相容性和力学相容性.动物实验研究表明:组织工程化三维仿骨支架诱导生长出新的骨小梁,并伴有β-TCP降解,这为修复或重建股骨头局部坏死区提供了一种有希望的新途径.     

外科植入物用TC20(Ti-6Al-7Nb)钛合金研究与应用

对TC20合金力学性能、生物学性能和临床应用进行了研究.合金棒材成分、组织与性能满足国际标准ISO5832要求;材料的生物学性能实验证明合金具有良好生物相容性,并能和骨组织形成良好的骨整合;近40例的临床应用表明疗效良好.     

二水硫酸钙/β-磷酸三钙/聚乳酸复合材料的制备及性能研究

本实验主要研究二水硫酸钙(CS)/β-磷酸三钙(β-TCP)/聚乳酸(PLA)复合材料的制备和性能。先将CS和β-TCP共混球磨,然后用溶液共混法制得CS和β-TCP总的质量分数为20%的聚乳酸三相复合材料,并制成2 mm×5mm×5 mm的片状颗粒。复合材料的抗拉强度测试结果表明,在CS与β-TCP总的质量分数不变的条件下,随着CS添加量的增多和β-TCP添加量的的减少,复合材料的抗拉强度呈下降趋势。经Tris溶液浸泡后,其质量由于降解而缓慢减少,并随着CS相对含量的增加,复合材料的质量减少速率逐渐减小。SEM结果显示,浸泡后的材料表面出现蚀孔与沉积现象。体外细胞培养结果表明,细胞可以在复合材料表面粘附和增殖,其细胞相容性与聚乳酸相当。实验结果表明,所得到的复合材料力学性能能够达到骨内固定材料使用的要求,具有良好的生物相容性,并且降解速度可调,具有作为新型可降解骨内固定材料使用的潜在可能。     

多孔镁表面生物活性β-TCP涂层的制备及其细胞相容性研究

采用化学沉积法在镁支架表面制备生物活性的β-TcP(磷酸三钙陶瓷)涂层,利用X射线衍射,扫描电子显微镜研究β-TCP涂层的相结构和表面形貌.并对表面改性的镁支架与类成骨细胞UMR106的体外生物相容性进行了详细研究.结果表明,表面改性后的镁支架浸提液细胞毒性为1级,即无细胞毒性;材料浸提液无细胞DNA毒性,对细胞周期无改变,也无异倍体细胞出现.实验结果证明,表面改性后的多孔镁具有良好的细胞相容性,是一种很有前景的新型骨组织工程支架材料.     

Rheology Feature of Simple Metal Melt

The rheology feature of Sb, Bi melt and alloys was studied using coaxial cylinder high-temperature viscometer. The results showed that the curve of torsion-rotational speed for Sb melt presents a linear relation in all measured temperature ranges, whereas for the Bi melt, the curve presents obvious non-Newtonian feature within the low temperature range and at relative high shear stress. The rheology feature of Sb80Bi20 and Sb20Bi80 alloy melts was well correlated with that of Sb and Bi, respectively. It is considered that the rheology behavior of Sb melt plays a crucial role in Sb80Bi20 alloy and that of Bi melt plays a crucial role in Sb20Bi80 alloy.     

Microstructures and Mechanical Properties of a Newly Developed Austenitic Heat Resistant Steel

The effect of heat treatment on the microstructures and mechanical properties of a newly developed austenitic heat resistant steel(named as T8 alloy) for ultra-supercritical applications have been studied. Results show that the main phases in the alloy after solution treatment are γ and primary MX. Subsequent aging treatment causes the precipitation of M_(23)C_6 carbides along the grain boundaries and a small number of nanoscale MX inside the grains. In addition, with increasing the aging temperature and time, the morphology of M_(23)C_6 carbides changes from semi-continuous chain to continuous network.Compared with a commercial HR3C alloy, T8 alloy has comparable tensile strength, but higher stress rupture strength. The dominant cracking mechanism of the alloy during tensile test at room temperature is transgranular, while at high temperature, intergranular cracking becomes the main cracking mode, which may be caused by the precipitation of continuous M_(23)C_6 carbides along the grain boundaries. Typical intergranular cracking is the dominant cracking mode of the alloy at all stress rupture tests.     

The 15th Global Foundry Sourcing Conference 2014held in Qingdao China

Organized by Suppliers China Co., Ltd and co-organized by the National Technical Committee 54 on Foundry of Standardization Administration of China, the 15th Global Foundry Sourcing Conference 2014 （hereinafter referred to as FSC 2014） was successfully held on Sep. 23rd in Grand Regency Hotel, Qingdao. More than 500 delegates from home and abroad attended this conference, including over 130 purchasers from 20 countries and 380 domestic and foreign suppliers.     

Secondary Recrystallization Behaviors of Grain-Oriented 6.5 wt% Silicon Steel Sheets Produced by Rolling and Nitriding Processes

By rolling and nitriding processes, 0.23- to 0.3-mm-thick grain-oriented 6.5 wt% silicon steel sheets were produced. The core losses of grain-oriented 6.5 wt% silicon steel at frequencies ranging from 400 Hz to 20 k Hz were lower than that of the grain-oriented 3 wt% silicon steel with the same thickness by 16.6–35.8%. The secondary recrystallization behavior was investigated by scanning electron microscopy, energy-dispersive spectroscopy, and electron backscattered diffraction. The results show that the secondary recrystallization in high-silicon steel sheets develops more completely as the nitrogen content increases after nitriding, secondary recrystallized grain sizes become larger, and the sharpness of Goss texture increases. Because more {110}116 grains in the subsurface and the central layer of the sheets have a lot of 20°–45° high-energy boundaries in addition to Goss grains, {110}116 can be the main component through selective growth during secondary recrystallization when the inhibitor quantity is not enough and inhibitor intensity is weaker. The increases in nitrogen content can increase the inhibitor intensity and hinder abnormal growth of a mount of {110}116 grains and therefore enhance the sharpness of Goss texture.     

Laser Cladded TiCN Coatings on the Surface of Titanium

Laser cladded coatings of TiCN were produced on the surface of titanium. To obtain the optimal techniques, several conditions were tested by varying the laser scanning rate. The choice of shielding gas was also studied. The cladded coatings were then evaluated from the surface mechanics point of view based on their microhardness. The microstructure of some interesting samples was investigated by optical micrographs (OM). The results showed that under the condition of fixed pulse frequency and pulse width, the laser scanning rate and the shielding gas are the main factors influencing the components of coatings. TiCN coatings were decompounded and oxidized during the cladding process in the condition of no shielding gas of N2. X-ray diffraction results indicated that the composite coatings composed of TiCN, TiC, Ti2N, and TiO2 were produced using appropriate techniques. The results indicated that the best condition in terms of the surface microhardness is obtained when the scanning rate is 1.5mm / s, the pulse frequency is 15Hz, the pulse width is 3.0ms, and N2 is chosen as the shielding gas. The microhardness of the composite coatings is about 1331kg · mm - 2, which is about 4 times that of the substrate. The optical micrographs indicated that the cladding zone is made up of TiCN, TiO2, and some interdendritic Ti, but the diffusion zone mainly consists of the dendrites phase, and the cladded depth is about 80?滋m, which is more than 2 times that of the laser nitrided sample. There were no microcracks or air bubbles in the cladded sample, which was cladded using the above optimal techniques.     

Microstructure and Mechanical Properties of X80 Pipeline Steel Joints by Friction Stir Welding Under Various Cooling Conditions

X80 pipeline steel plates were friction stir welded(FSW) under air, water, liquid CO_2 + water, and liquid CO_2 cooling conditions, producing defect-free welds. The microstructural evolution and mechanical properties of these FSW joints were studied. Coarse granular bainite was observed in the nugget zone(NZ) under air cooling, and lath bainite and lath martensite increased signifi cantly as the cooling medium temperature reduced. In particular, under the liquid CO_2 cooling condition, a dual phase structure of lath martensite and fi ne ferrite appeared in the NZ. Compared to the case under air cooling, a strong shear texture was identifi ed in the NZs under other rapid cooling conditions, because the partial deformation at elevated temperature was retained through higher cooling rates. Under liquid CO_2 cooling, the highest transverse tensile strength and elongation of the joint reached 92% and 82% of those of the basal metal(BM), respectively, due to the weak tempering softening. A maximum impact energy of up to 93% of that of the BM was obtained in the NZ under liquid CO_2 cooling, which was attributed to the operation of the dual phase of lath martensite and fi ne ferrite.     

INDUSTRY NEWS

China Securities News reported on March 21, 2014： Guangdong Hongtu Wuhan Die Casting Co., Ltd. （Wuhan Hongtu）, a wholly owned subsidiary of Guangdong Hongtu Technology （Holdings） Co., Ltd., held a groundbreaking ceremony recently. With the registered capital of 50 million Yuan, Wuhan Hongtu has a total land area of 100,000 square meters and a plant construction area of 72,000 square meters. It is expected to have a production capacity of about 30,000 tonnes of aluminum castings annually after it is put into production.     

Microstructure,Mechanical Properties and Corrosion Behavior of Extruded Mg–Zn–Ag Alloys with Single-Phase Structure

Mg–Zn–Ag alloys have been extensively studied in recent years for potential biodegradable implants due to their unique mechanical properties,biodegradability and biocompatibility.In the present study,Mg–3Zn-x Ag(wt%,x=0.2,0.5 and0.8)alloys with single-phase crystal structure were prepared by backward extrusion at 340°C.The addition of Ag element into Mg–3Zn slightly influences the ultimate tensile strength and microstructure,but the elongation firstly increases from12%to 19.8%and then decreases from 19.8%to 9.9%with the increment of Ag concentration.The tensile yield strength,ultimate tensile strength and elongation of Mg–3Zn–0.2Ag alloy reach up to 142,234 MPa and 19.8%,respectively,which are the best mechanical performance of Mg–Zn–Ag alloys in the present work.The extruded Mg–3Zn–0.2Ag alloy also possesses the best corrosion behavior with the corresponding corrosion rate of 3.2 mm/year in immersion test,which could be explained by the single-phase and uniformly distributed grain structure,and the fewer twinning.     

Study on Properties of Pulse Electrodeposited RE-Ni-W-P-SiC Composite Coatings

The effects of pulse frequency f and duty cycle r on the deposition rate, composition, morphology, and hardness of pulse electrodeposited RE （rare earth）-Ni-W-P-SiC composite coatings have been studied. The results indicate that pulse current can improve the deposition rate of RE-Ni-W-P-SiC composite coatings; W, P, and SiC contents in the coating decrease with the increase of pulse frequency and reach the lowest value at f = 33Hz, whereas the RE content in the composite coatings increases with the increase of pulse frequency. SiC content decreases with the increase of duty cycle, W content reaches the lowest value, and P content reaches the highest value at r = 0.4; pulse current and RE can lead to smaller size of the crystalline grains; however, the effects of different pulse frequency and duty cycle on the morphologies of RE-Ni-W-P-SiC composite coatings are not obvious. The hardness of RE-Ni-W-P-SiC composite coatings is the highest when the duty cycle is at 0.6 and 0.8 and pulse frequency is at 50Hz. At the same pulse frequency, the hardness of RE-Ni-W-P-SiC composite coatings at r= 0.8 is higher than that at r= 0.6.