Recent progress in improving ductility of ultra-high strength nanostructured metals

2004 ◽  
Vol 10 (6) ◽  
pp. 527-531 ◽  
Author(s):  
E. Ma
Keyword(s):  
Recent Progress ◽  
High Strength ◽  
Nanostructured Metals

scholarly journals Recent Progress in 3D Printing of Elastic and High-Strength Hydrogels for the Treatment of Osteochondral and Cartilage Diseases

2020 ◽  
Vol 8 ◽  
Author(s):  
Wenli Dai ◽  
Muyang Sun ◽  
Xi Leng ◽  
Xiaoqing Hu ◽  
Yingfang Ao
Keyword(s):  
Articular Cartilage ◽  
3D Printing ◽  
Recent Progress ◽  
High Strength ◽  
Cartilage Defects ◽  
High Water Content ◽  
Covalent Bonds ◽  
Cartilage Diseases ◽  
Articular Cartilage Defects ◽  
And Cartilage

Despite considerable progress for the regenerative medicine, repair of full-thickness articular cartilage defects and osteochondral interface remains challenging. This low efficiency is largely due to the difficulties in recapitulating the stratified zonal architecture of articular cartilage and engineering complex gradients for bone-soft tissue interface. This has led to increased interest in three-dimensional (3D) printing technologies in the field of musculoskeletal tissue engineering. Printable and biocompatible hydrogels are attractive materials for 3D printing applications because they not only own high tunability and complexity, but also offer favorable biomimetic environments for live cells, such as porous structure, high water content, and bioactive molecule incorporation. However, conventional hydrogels are usually mechanically weak and brittle, which cannot reach the mechanical requirements for repair of articular cartilage defects and osteochondral interface. Therefore, the development of elastic and high-strength hydrogels for 3D printing in the repairment of cartilage defects and osteochondral interface is crucial. In this review, we summarized the recent progress in elastic and high-strength hydrogels for 3D printing and categorized them into six groups, namely ion bonds interactions, nanocomposites integrated in hydrogels, supramolecular guest–host interactions, hydrogen bonds interactions, dynamic covalent bonds interactions, and hydrophobic interactions. These 3D printed elastic and high-strength hydrogels may provide new insights for the treatment of osteochondral and cartilage diseases.

Concrete in Canada: 50 years of progress — present concerns

2018 ◽  
Vol 45 (2) ◽  
pp. 117-124
Author(s):  
Pierre-Claude Aïtcin ◽  
William Wilson ◽  
Sidney Mindess
Keyword(s):  
Silica Fume ◽  
Material Properties ◽  
Recent Progress ◽  
High Strength ◽  
Blended Cements ◽  
The Past ◽  
Concrete Admixtures

Over the past 50 years, concrete in Canada has evolved from a simple robust material to a complex composite with impressive improvements in the material properties. Due to the development of water reducers and silica fume, the performance of concrete has improved from the conventional 30 MPa concrete before the CN Tower (1973) to the ultra-high strength 200 MPa concrete used in the Passerelle de Sherbrooke (1998). This paper retraces this evolution of concrete with a focus on both the technical improvements and the important structures built with these technologies. Recent progress in blended cements and poly-carboxylate ether superplasticizers is also presented, along with the concerns and current challenges to ensure an optimized and safe use of these new concrete admixtures.

scholarly journals Current Challenges and Opportunities in Microstructure-Related Properties of Advanced High-Strength Steels

2020 ◽  
Vol 51 (11) ◽  
pp. 5517-5586 ◽  
Author(s):  
Dierk Raabe ◽  
Binhan Sun ◽  
Alisson Kwiatkowski Da Silva ◽  
Baptiste Gault ◽  
Hung-Wei Yen ◽  
...  
Keyword(s):  
Recent Progress ◽  
High Strength Steels ◽  
High Strength ◽  
Advanced Characterization ◽  
Critical Discussion ◽  
Press Hardening ◽  
Advanced High Strength Steels ◽  
Bainitic Steels ◽  
Challenges And Opportunities ◽  
Recent Developments

Abstract This is a viewpoint paper on recent progress in the understanding of the microstructure–property relations of advanced high-strength steels (AHSS). These alloys constitute a class of high-strength, formable steels that are designed mainly as sheet products for the transportation sector. AHSS have often very complex and hierarchical microstructures consisting of ferrite, austenite, bainite, or martensite matrix or of duplex or even multiphase mixtures of these constituents, sometimes enriched with precipitates. This complexity makes it challenging to establish reliable and mechanism-based microstructure–property relationships. A number of excellent studies already exist about the different types of AHSS (such as dual-phase steels, complex phase steels, transformation-induced plasticity steels, twinning-induced plasticity steels, bainitic steels, quenching and partitioning steels, press hardening steels, etc.) and several overviews appeared in which their engineering features related to mechanical properties and forming were discussed. This article reviews recent progress in the understanding of microstructures and alloy design in this field, placing particular attention on the deformation and strain hardening mechanisms of Mn-containing steels that utilize complex dislocation substructures, nanoscale precipitation patterns, deformation-driven transformation, and twinning effects. Recent developments on microalloyed nanoprecipitation hardened and press hardening steels are also reviewed. Besides providing a critical discussion of their microstructures and properties, vital features such as their resistance to hydrogen embrittlement and damage formation are also evaluated. We also present latest progress in advanced characterization and modeling techniques applied to AHSS. Finally, emerging topics such as machine learning, through-process simulation, and additive manufacturing of AHSS are discussed. The aim of this viewpoint is to identify similarities in the deformation and damage mechanisms among these various types of advanced steels and to use these observations for their further development and maturation.

Advances in Bonding Technology for Electronic Packaging

1993 ◽  
Vol 115 (2) ◽  
pp. 201-207 ◽  
Author(s):  
Chin C. Lee ◽  
Chen Y. Wang ◽  
Goran Matijasevic
Keyword(s):  
Cross Section ◽  
Recent Progress ◽  
High Strength ◽  
Acoustic Microscopy ◽  
Bonding Layer ◽  
Alloy Formation ◽  
Advantages And Disadvantages ◽  
Bonding Technology ◽  
Higher Temperature ◽  
Good Uniformity

Recent progress in bonding materials is briefly reviewed with highlights of some of the advantages and disadvantages of the various attachment processes. The principle and experimental results of bonding with multilayer structures of Au-Sn and Au-In are presented. Using solid state as well as liquid phase diffusion of the multilayers, bonding temperatures less than the final melting point of the alloy can be used. This technique therefore allows reversal of the conventional soldering step hierarchy allowing a higher temperature process to follow the multilayer bonding step. Proper deposition of the multilayers inhibits oxidation of tin or indium. Die attachment experiments confirmed that high quality bonding can be obtained as seen in the void-free bonding layer images done by scanning acoustic microscopy. Cross-section examinations with SEM and EDX show near-eutectic alloy formation of good uniformity. Thermal shock tests confirmed the high strength of these solder alloys.

Simulation on Nanostructured Metals Based on Multiscale Crystal Plasticity Considering Effect of Grain Boundary

2012 ◽  
Vol 706-709 ◽  
pp. 1751-1756 ◽  
Author(s):  
Yoshiteru Aoyagi ◽  
Tomotsugu Shimokawa ◽  
Kazuyuki Shizawa ◽  
Yoshiyuki Kaji
Keyword(s):  
Grain Boundary ◽  
Crystal Plasticity ◽  
High Strength ◽  
Nanostructured Metals ◽  
Hardening Law ◽  
Crystal Plasticity Model ◽  
Ultrafine Grained ◽  
Dislocation Behavior ◽  
Strain Responses ◽  
Peculiar Behavior

Ultrafine-grained metals whose grain size is less than one micron have attracted interest as high strength materials. Whereas nanostructured metals produced by severe plastic deformation express remarkably peculiar behavior in both material and mechanical aspects, its mechanism has been clarified by neither experimental nor computational approaches. In this study, we develop a multiscale crystal plasticity model considering an effect of grain boundary. In order to express release of dislocation from grain boundaries, information of misorientation is introduced into a hardening law of crystal plasticity. In addition, carrying out FE simulation for FCC polycrystal, the stress-strain responses such as increase of yield stress due to existence of grain boundary are discussed. We investigate comprehensively the effect of dislocation behavior on the material property of nanostructured metal.

The Effect of Grain Size and Strain Rate on the Tensile Ductility of Bulk Nanostructured Metals and Alloys

2009 ◽  
Vol 633-634 ◽  
pp. 393-410
Author(s):  
Guo Yong Wang ◽  
Jian She Lian ◽  
Qing Jiang
Keyword(s):  
Grain Size ◽  
Strain Rate ◽  
Room Temperature ◽  
Tensile Ductility ◽  
High Strength ◽  
Metals And Alloys ◽  
New Materials ◽  
Electrodeposition Technique ◽  
Nanostructured Metals ◽  
Coherent Property

The nanostructured metals and alloys are under intensive research worldwide and being developed into bulk forms for application. While these new materials offer record-high strength, their ductility is often inadequate and sometime rendering them unusable. Besides tailoring the nanostructure to achieve coexisting high strength and high ductility, to uncover the coherent property of this material is also important. This article reviews the recent researches finished in our lab. A set of nanostructured metals and alloys were synthesized by a direct current electrodeposition technique, and the effect of grain size and strain rate on the mechanical properties stressing on tensile ductility was systemically studied by tensile test at room temperature.

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