1、Progresses and Grand Challenges for the Materials Science and Engineering (MSE),材料科学与工程的进展与挑战,2011. 06,Outlines,Introduction to Materials Science and Engineering（材料科学与工程简介）Challenges for the Materials Science（材料科学所取得的进展及遇到的挑战） Others,Introduction to Materials Science and Engineering (MSE),Several si
2、mple questions:,What do materials scientists and engineers study? How sheet steel can be processed to produce a high-strength, lightweight, energy absorbing, malleable material used in the manufacture of car chassis? Can we make flexible and lightweight electronic circuits using plastics? What is a
3、“smart material”?,“Engineers make things. They make them out of materials.”,Materials science and engineering (MSE) is an interdisciplinary field concerned with inventing new materials and improving previously known materials by developing a deeper understanding of the microstructure-composition- sy
4、nthesis-processing relationships. The term composition means the chemical make-up of a material. The term structure means a description of the arrangement of atoms. The term synthesis refers to how materials are made from naturally occurring or man-made chemicals. The term processing means how mater
5、ials are shaped into useful components to cause changes in the properties of different materials. In materials science, the emphasis is on the underlying relationships between the synthesis and processing, structure and properties of materials. In materials engineering, the focus is on how to transl
6、ate or transform materials into a useful device or structure.,Tetrahedron of MSE,(组成与微观结构),(性能),(使用性能与成本),(制备与加工),Composition: the periodic table,Crystal structure（晶体结构）,cubic,orthorhombic,Rhombohedral,Tetragonal,Monoclinic,Triclinic,Hexagonal,Summary of 14 Bravais space lattice.,quartz crystal,Bi2S
7、r2CaCu2O8+,Hemoglobin with backbone trace colored by chain and spacefilled hemes.,Crystal structure,Diamond,Microstructure（微观结构）,gypsum crystals,Some polymers form interesting crystals.,Surface of an aluminium oxide “as fired“,Casted titanium,Elastic modulus (E) Strength: yield strength, tensile str
8、ength, compressive strength etc. Fracture toughness Density etc.,Mechanical properties（力学性能）,Sress-strain diagram for mild steel.,Thermal properties （热性能）,The maximum service temperature (Tmax) Thermal conductivity Heat capacity Thermal diffusivity etc.,The heat capacity function for low temperature
9、s.,Electrical, magnetic and optical properties Chemical properties（电、磁、光及化学性能）,The classes of process.,Raw materials:Chemical methodsPhysical methods,Synthesis and processing （制备与加工）,Examples of the families and classes of manufacturing processes.,Classification of materials （材料的分类）,Integrated aeros
10、pike engines,Titanium hot structures,Composite propellant tanks,Composite aeroshell,Metallic thermal protection tiles,Electrically operated fight surface,Six conventional families of engineering materials（工程材料的六种分类）,Metals have relatively high stiffness, measured by the modulus, E. Most, when pure,
11、are soft and easily deformed. Ceramics are non-metallic, inorganic solid, like porcelain or alumina. Glasses are non-crystalline (amorphous) solods. Polymers are organic solids based on long chains of carbon (or, in a few, silicon) atoms. Elastomers - the materials of rubber bands and running shoes
12、- are polymers with the unique property that their stiffness, E is extremely low. Hybirds- composite materials made by combining two or more of others.,Aerospace materials: C-C composites, SiO2, Amorphous silicon, Al-alloys, Superalloys Biomedical materials: Titanium alloys, Stainless steels, Shape-
13、memory alloys, Plastics, PZT Electronic materials: Si, GaAs, Ge, BaTiO3, PZT, YBa2Cu3O7-x, Conducting polymers Energy technology and environmental technology: UO2, Ni-Cd, ZrO2, LiCoO2, Amorphous Si: H, TiO2 nanomaterials Magnetic materials: Fe, Fe-Si, NiZn, Co-Pt-Ta-Cr, Fe2O3, Tb0.23Dy0.77Fe2, LaCaM
14、nO3 film Photonic or optical materials: SiO2, GaAs, Glasses, Al2O3, YAG, LiNbO3 Smart materials: PZT, Ni-Ti shape memory alloys, MR fluids, polymer gels Structural materials: Steels, Aluminum alloys, Concrete, Fiberglass, Plastics, Wood,Functional classification of materials（材料的功能性分类）,Materials desi
15、gn and selection （材料设计与选择）,Embodiment sketches for the first concept: direct pull, levered pull, geared pull and spring-assisted pull. Each system is made up of components that perform a sub-function.,The narrowing of material search spaces as design constrains are applied.,The interaction between d
16、esign requirements, material shape and process.,The strategy applied to materials. The same strategy is later adapted to select processes. There are four steps: translation, screening, ranking and supporting information.,Materials consumption, energy and environment （材料的消耗、能源与环境危机）,The consumption o
17、f hydrocarbons (left-hand column) and of engineering materials (the other columns).,The growth of materials consumption,Most materials are being consumed at a rate that is growing exponentially with time, simply because both population and living standards grow exponentially.,Exponential growth. Con
18、sumption rate C doubles in a time td=70/r, where r is the annual growth rate.,Non-renewable resources!,The materials life cycle,The materials life cycle. Ore and feedback are mined and processed to yield a material. This is manufactured into a product that is used and, at the end of its life, discar
19、ded or recycled. Energy and materials are consumed in each phase, generating waste heat and solid, liquid and gaseous emissions.,An input-output diagram for PET production and for bottle production.,A simplified input-output diagram for the recycling of plastics to recover PET, and its use to make l
20、ower-grade products such as fleece.,Approximate values for the energy consumed at each phase for a range of products. The column show the approximate embodied energy (Mat.), energy to manufacture (Manu.), use energy over design life (Use) and energy for disposal (Displ.).,Rational use of the databas
21、e starts with an analysis of the phase of life to be targeted. The decision then guides the method of selection to minimize the impact of the phase on the environment.,Challenges for the Materials Science and Engineering (MSE) in the 21st Century,The top ten advances in materials science in the past
22、 50 years,Should an advance alter our daily lives, or does fundamentally changing the research arena count?,Materials today, 2008, 11, (1-2),International technology roadmap for semiconductors (ITRS,国际半导体技术蓝图) Scanning probe microscopes (扫描探针显微镜) Giant magnetoresistive effect (巨磁电阻效应) Semiconductor
23、lasers and LEDs (半导体激光器与LED照明) National nanotechnology initiative (美国国家纳米技术计划) Carbon fiber reinforced plastics (碳纤维增强塑料) Materials for Li ion batteries (Li离子电池材料) Carbon nanotubes (碳纳米管) Soft lithography (软模板印刷术) Metameterials (超材料),International technology roadmap for semiconductors (ITRS),Its not
24、 a research discovery, solely away of organizing research priorities and planning R&D. It sets out goals for innovation, technology needs, and measure for progress that all can sign up to in the fiercely competitive microelectronics industry within a 15-year horizon. The first national technology ro
25、admap efforts began in 1992. The new 2007 edition will have 18 chapters and over 1000 pages, it is estimated.,Scanning probe microscopes,The invention of the scanning tunneling microscope (STM) by Heinrich Rohrer and Gerd Binnig at IBMs Zurich Research Laboratory was deservedly awarded the Nobel Pri
26、ze for Physics in 1986. The fabrication of the first STM in March 1981 in IBMs Zurich Research Laboratory The development of the atomic force microscope (AFM) in 1986 at IBM Almaden Research Center and Stanford Univeristy These two invention have opened doors into the nanoscale word, and ultimately
27、to nanotechnology. The ultimate impact of these tools will surely cove a huge range of disciplines, including materials science, (opto)electronics, medicine, catalysis, and they will offer new solutions to key problems such as energy and the environment.,All of the techniques are based upon scanning
28、 a probe just above a surface whilst monitoring some interaction between the probe and the surface. STM - is the tunnelling current between a metallic tip and a conducting substrate which are in very close proximity but not actually in physical contact. AFM - is the van der Waals force between the t
29、ip and the surface; this may be either the short range repulsive force (in contact-mode) or the longer range attractive force (in non-contact mode).,Nickel (110),The smallest logo using 35 xenon atoms on a Ni plate.,The Millipede project,High performance STM image showing atomic resolution on Si(111
30、)7x7,Au(111) polycrystalline film on a glass substrate - in pure contact mode AFM.,Giant magnetoresistive effect,The 2007 Nobel Prize for Physics went jointly to Albert Fert of University Paris-Sud, France, and Peter Grunberg of Forschungszentrum Julich, Germany, for independently discovering the gi
31、ant magnetoresistance (GMR). Giant magnetoresistance (GMR) is a quantum mechanical effect, a type of magnetoresistance effect, observed in thin film structures composed of alternating ferromagnetic and nonmagnetic metal layers.,Magnetoresistance effect Magnetoresistive effect (MR): 1857, Lord Kelvin
32、 GMR: 1988 Tunnel magnetoresistance (TMR): 1975, Michel Julliere Colossal magnetoresistance (CMR): 1993, von Helmolt Anisotrope magnetoresistance (AMR): 1857, Thomson,Applications of GMR: The read heads in modern hard drives. The magnnetoresistive random access memory (MRAM), a type of non-volatile
33、semiconductor memory,Semiconductor lasers and LEDs,The semiconductor lasers and light-emitting diodes (LEds) are now the basis of telecommunications, CD and DVD players, laser printers. The advent of solid-state lighting is also likely to make a significant contribution to reducing our energy usage.
34、 A light-emitting diode (LED) is a semiconductor diode that emits incoherent narrow-spectrum light when electrically biased in the forward direction of the p-n junction, as in the common LED. A laser diode is a laser where active medium is a semiconductor. The most common and practical type of laser
35、 is formed from a p-n junction and powered by injected current. So these devices are sometimes referred to as injection laser diodes to distinguish them from (optically) pumped lasers diodes.,A packaged laser diode with penny for scale.,Green, blue and red LEDs.,Image of actual laser diode chip show
36、n on the ear of a needle for scale.,Why LEDs?,Advantages Great stride in power and efficiency100,000 hours of work compared to 1000 hours of life time for incandescent bulbs. LEDs :capable of emitting light of an intended color without the use of color filters that traditional lighting methods requi
37、re. The shape of the LED package allows light to be focused. Incandescent and fluorescent sources often require an external reflector to collect light and direct it in a useable manner. LEDs are insensitive to vibration and shocks, unlike incandescent and discharge sources. LEDs are built inside sol
38、id cases that protect them, making them hard to break and extremely durable,White LEDs,Application,National nanotechnology initiative,US president Bill Clinton announced the establishment of the National Nanotechnology Initiative (NNI) in 2000. In 2003, US president George W. Bush signed into law th
39、e 21st Nanotechnology Research and Development Art.,Goal of the NNI Advance a world-class nanotechnology research and development program. Foster the transfer of new technologies into products for commercial and public benefit. Develop and sustain educational resources, a skilled workforce, and the
40、supporting infrastructure and tools to advance nanotechnology Support responsible development of nanotechnology,Carbon fiber reinforced plastics,Carbon fiber reinforced plastics (CFRP or CRP) is a very strong, light and expansive composite material. It has many applications in aerospace and automoti
41、ve fields, as well as in sailboats, and notably in modern bicycles and motorcycles, where its high strength to weight ratio is of importance. Carbon fiber reinforced plastics (CFRPs) have an almost infinite service lifetime when protected from the sun.,A 6 m diameter carbon filament compared to a hu
42、man hair.,Tail of an RC helicopter, made of CFRP,CFRPs were at the heart of this bike built by Lotus Engineering for the 1992 Barcelona Olympics. It helped Chris Boardman win gold.,Materials for Li ion batteries,Li ion batteries are a type of rechargeable battery in which a Li ion move between the a
43、node and cathode.,“Imagine your electrical equipment powered by Lithium ion battery refuse to die out of charge. Imagine your 2 hour battery backup of your laptop increases to 20 hours. 6 days of standby time of cell phones increases to 60 days i.e 2 months ( charging a mobile just 6 times a year !
44、woooaaahhh ) :-O ,Working principle,Li ion battery uses LiCoO2 (or LiMnO2, LiFePO4, Li2FePO4F) as positive electrode - cathode - and a high crystallized special carbon as negative electrode-anode.,Features of Li ion battery: High energy density that reaches 400 Wh/L or 160Wh/Kg High voltage. Nominal
45、 voltage of 3,6V or even 3,7V on newer Li-Ion batteries No memory effect. Can be charged any time, but they are not as durable as NiMH and NiCd batteries High charge currents (0,5-1A) that lead to small charging times (around 2-4 hours) Flat discharge voltage allowing the device to stable power thro
46、ughout the discharge period Typical charging Voltage 4,2 0,05V Charging method: constant current - constant voltage (CV-CC) Typical operation voltage 2,8V to 4,2V Recommended temperature range 0-40oC,Carbon nanotubes,Carbon nanotubes (CNTs) are allotropes of carbon with a nanostructure that can have
47、 a length-to-diameter ratio greater than 1,000,000. They exhibit extraordinary strength and unique electrical properties, and are efficient conductors of heat. These cylindrical carbon molecules have novel properties that make them potentially useful in many applications in nanotechnology, electroni
48、cs, optics and other fields of materials science, as well as extensive use in arcology and other architectural fields.,3D-modle of three types of single-walled carbon nanotubes.,The animation of a rotating carbon nanotube shows its 3D structure.,Types of carbon nanotubes and related structures,Singl
49、e-walled Multi-walled Fullerite Torus Nanobud,Soft lithography,In technology, soft lithography refers to a set of methods for fabricating or replicating structures using “elastomeric stamps, molds, and conformable photomasks“. It is called “soft“ because it uses elastomeric materials most notably PD
50、MS. Soft lithography is generally used to construct features measured on the nanometer scale. Micro Contact Pronting (CP) Replica Molding (REM) Microtransfer Molding (TM), Micromolding in capillaries (MIMIC) Solvent-assisted Micromolding (SAMIM),Figure 1 - “Inking“ a stamp. PDMS stamp with pattern is placed in Ethanol and ODT solution.,
