宝石专业《材料工艺学》探究式教学改革实践

河北地质大学宝石及材料工艺学专业《材料工艺学》课程存在诸如重视度不够、课程不衔接、授课方法陈旧、学生学习效果较差等问题,本论文从授课目的、授课内容、授课方法、考核方式等方面进行探究式教学改革。如从化学、物理等材料本质出发分析宝石的特征和应用,采用互动、启发式教学、微课等手段提升教学效果,以学科论文加开卷考试的考核手段考察学生的综合能力,对于解决上述问题取得了显著的效果。

Influence of FeCrAl fiber on microstructure and mechanical properties of FeCrAl(f)/HA composites

FeCrAl fiber-reinforced hydroxyapatite（HA） biocomposites（FeCrAl（f）/HA） were fabricated by the hot pressing technique.The metallographic microscopy,X-ray diffractometry,scanning electron microscopy（SEM） and energy dispersive spectroscopy（EDS） were used to observe and analyze the microstructure and composition of FeCrAl（f）/HA composites,respectively.The mechanical properties of FeCrAl（f）/HA composites were measured by the three-point-bending test.The results show that the composite can be reinforced by FeCrAl fiber and enhanced gradually,and then declined with the increase of the content of FeCrAl fiber（0-11%,volume fraction） in the whole range of experiments.Both the HA matrix and FeCrAl fiber integrate very tightly and bit into each other very deeply and counter-diffusion takes place to some extent at two-phase interface.The optimum parameters of FeCrAl（f）/HA composite are diameter of 22 μm,length of 1-2 mm and of volume faction of about 7% for FeCrAl fibers.

Fabrication of carbon nanotube reinforced AZ91D composite with superior mechanical properties

AZ91D alloy composites with1.0%CNTs have been fabricated by a method combined ball milling with stirring casting.The composite was investigated using optical microscopy(OM),X-ray diffraction(XRD),Fourier transform infrared spectroscope(FT-IR),scanning electron microscope(SEM),transmission electron microscope(TEM)and room temperature(RT)tensile test.Theresults show that CNTs were homogeneously distributed in the matrix and maintained integrated structure.The yield strength andductility of AZ91D/CNTs composite were improved by47.2%and112.2%,respectively,when compared with the AZ91alloy.Theuniform distribution of CNTs and the strong interfacial bonds between CNT and the matrix are dominated to the simultaneousimprovement of yield strength and ductility of the composite.In addition,the grain refinement as well as the finerβphase(Mg17Al12)with homogenous distribution in the matrix can also slightly assist to the enhancement of the mechanical properties of thecomposite.

Preparation and Properties of a New Type of Poly(butylene-terephthalate)with Layered Silicate Nanocomposites

In this paper, poly(butylene-terephthalate)-layered silicate of clay nanocomposites (NPBT) are reported. Their thermal properties, heat distortion temperature (HDT) and crystallization nucleation are investigated. NPBT samples have apparent viscosity over 0.85, HDT of 30℃ to 50℃ higher than that of poly (butylene-terephthalate) (PBT) for clay load from 1.0% to 10.0% (by mass), and higher capability to accommodate clay than other polymers. The nonisothermal crystallization experiments indicate that the better thermal degradation behavior and crystallization rate of NPBT are 50% higher than PBT, and its injection mould processing temperature is lowered from 110℃ to 55℃. NPBT samples are characterized by several techniques. X-ray shows an original clay interlayer distance enlarged from 1.0 nm to 2.5 nm, while both TBM and AFM indicate an average size from 30nm to lOOnm of exfoliated clay layers, and 3%(by mass) of particle agglomeration being phase separated from PBT matrix, which are factors on some mechanical properties decrease of NPBT. The disappearance of spherulitic morphology in NPBT resulted from layers nucleation is detected. Improving NPBT properties by treating clay with long chain organic reagent and controlling the way to load it is suggested.

Effects of infiltration parameters on mechanical and microstructural properties of tungsten wire reinforced Cu_(47)Ti_(33)Zr_(11)Ni_6Sn_2Si_1 metallic glass matrix composites

Cu47Ti33Zr11Ni6Sn2Si1-based bulk metallic glass matrix composites reinforced with tungsten wires were fabricated by infiltration process at different temperatures （850, 900, 950 and 1000 °C） and time （10, 20 and 30 min） in a quartz or a steel tube. The mechanical tests were carried out by scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The results show that the maximum strength and total strain of the composite are 1778 MPa and 2.8% fabricated in steel tube at 900 °C for 10 min, and 1582 MPa and 3.6% fabricated in quartz tube at 850 °C for 10 min, respectively.

Effects of Steaming on the Tensile Mechanical Properties of Cashmere Fiber

The cashmere yarns were set in steam of 120℃ for 5 minutes after they had been extended to about 3% and wrapped onto the glass mandrels, which was relevant to the industrial setting processes. The effects of the steaming on the tensile mechanical properties of cashmere fiber are investigated. The extension in ' yield region' and the extension at rupture of the set cashmere fiber are obviously decreased.

Tailoring microstructure and mechanical properties of aluminum matrix composites reinforced with novel Al/CuFe multi-layered core-shell particles

Aluminum matrix composites(AMCs), reinforced with novel pre-synthesized Al/Cu Fe multi-layered coreshell particles, were fabricated by different consolidation techniques to investigate their effect on microstructure and mechanical properties. To synthesize multi-layered Al/Cu Fe core-shell particles, Cu and Fe layers were deposited on Al powder particles by galvanic replacement and electroless plating method, respectively. The core-shell powder and sintered compacts were characterized by using X-ray diffraction(XRD), scanning electron microscopy(SEM) equipped with energy dispersive spectroscopy(EDX), pycnometer, microhardness and compression tests. The results revealed that a higher extent of interfacial reactions, due to the transformation of the deposited layer into intermetallic phases in spark plasma sintered composite, resulted in high relative density(99.26%), microhardness(165 HV0.3) and strength(572 MPa). Further, the presence of un-transformed Cu in the shell structure of hot-pressed composite resulted in the highest fracture strain(20.4%). The obtained results provide stronger implications for tailoring the microstructure of AMCs through selecting appropriate sintering paths to control mechanical properties.

Analysis on Sichuan Folk Furniture Technical Characteristics： From Craft Aesthetics Perspective

The technical characteristics of Sichuan folk furniture were studied from craft aesthetic perspective. The features of Sichuan folk furniture material, technology and structure were analyzed through literature review, field investigation and expert interview methods, the technical characteristics of Sichuan folk furniture were re-analyzed from craft aesthetic perspective rather than the traditional material and technique research perspectives. The study shows that Sichuan folk furniture technical features contain not only cultural spirit and aesthetic consciousness, but distinctive aesthetic personality as well. Sichuan folk furniture technical characteristics convey Chinese traditional design philosophy, such as theory is based on objects, and it is highly concentrated and concise of aesthetic sentiment in Sichuan folk aesthetic temperament and interest.

Efficient organic solar cells with low-temperature in situ prepared Ga_(2)O_(3) or In_(2)O_(3) electron collection layers

Facile synthesis of an interfacial layer in organic solar cells (OSCs) is important for broadening material designs and upscaling photovoltaic conversion efficiency (PCE).Herein,a mild solution process of spin-coating In(acac)3and Ga(acac)3isopropanol precursors followed by low-temperature thermal treatment was developed to fabricate In_(2)O_(3)and Ga2O3cathode buffer layers (CBLs).The introduction of In_(2)O_(3)or Ga2O3CBLs endows PM6:Y6-based OSCs with outstanding performance and high PCEs of 16.17%and 16.01%,respectively.Comparison studies present that the In_(2)O_(3)layer possesses a work function (WF) of 4.58 eV,which is more favorable for the formation of ohmic contact compared with the Ga2O3layer with a WF of 5.06 eV and leads to a higher open circuit voltage for the former devices.Electrochemical impedance spectroscopy was performed to reveal how In_(2)O_(3)and Ga2O3affect the internal charge transfer and the origin of their performance difference.Although In_(2)O_(3)possesses lower series resistance loss,Ga2O3has a higher recombination resistance,which enhances the device fill factor and compensates for its series resistance loss to some extent.Comparative analysis of the photo-physics of In_(2)O_(3)and Ga2O3suggests that both are excellent CBLs for highly efficient OSCs.