scholarly journals Structure-property relations and the design of Fe-4Cr-C base structural steels for high strength and toughness

1980 ◽  
Vol 11 (3) ◽  
pp. 441-457 ◽  
Author(s):  
B. V. Narasimha Rao ◽  
G. Thomas
2019 ◽  
Vol 71 (4) ◽  
Author(s):  
Qinghua Meng ◽  
Tie Jun Wang

Cellulose nanopaper, which consists of a porous network of cellulose nanofibrils (CNFs), exhibits excellent mechanical properties with high strength and toughness. The physical mechanisms, including a realizable reduction of defect size in the nanopaper and facile formation/reformation of hydrogen bonds among CNFs, suggest a bottom-up material design strategy to address the conflict between strength and toughness. A thorough exploration of the rich potential of such a design strategy requires a fundamental understanding of its mechanical behavior. In this review, we supply a comprehensive perspective on advances in cellulose nanopaper mechanics over the most recent two decades from the three aspects of mechanical properties, structure–property relationship and microstructure-based mechanical modeling. We discuss the effects of size, orientation, polymerization degree, and isolate origins of CNFs; density or porosity and humidity of nanopaper; and hemicellulose and lignin on the mechanical properties of cellulose nanopaper. We also discuss the similarities and differences in the microstructure, mechanical properties, and toughening mechanisms between cellulose nanopaper and cellulose nanocrystal (CNC) nanopaper, chitin nanopaper, carbon nanotube (CNT) nanopaper, and graphene nanopaper. Finally, we present the ideas, status quo, and future trends in mechanical modeling of cellulose nanopaper, including atomistic- and microscale-level numerical modeling, and theoretical modeling. This review serves as a modest spur intended to induce scientists to present their valuable contributions and especially to design more advanced cellulose nanopapers and promote the development of their mechanics.


Alloy Digest ◽  
1981 ◽  
Vol 30 (7) ◽  

Abstract SAE 8642 is a triple-alloy steel that can be hardened by austenitizing and quenching in oil. This steel has moderate hardenability with relative high strength and toughness, especially in the quenched-and-tempered condition. It is used in a wide range of components, parts and tools; examples are bolts, shafts, gears, wrenches, axles and housings. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: SA-382. Producer or source: Alloy steel mills and foundries.


JOM ◽  
2021 ◽  
Author(s):  
Luis Zelaya-Lainez ◽  
Giuseppe Balduzzi ◽  
Olaf Lahayne ◽  
Kyojiro N. Ikeda ◽  
Florian Raible ◽  
...  

AbstractNanoindentation, laser ablation inductively coupled plasma mass spectroscopy and weighing ion-spiked organic matrix standards revealed structure-property relations in the microscopic jaw structures of a cosmopolitan bristle worm, Platynereis dumerilii. Hardness and elasticity values in the jaws’ tip region, exceeding those in the center region, can be traced back to more metal and halogen ions built into the structural protein matrix. Still, structure size appears as an even more relevant factor governing the hardness values measured on bristle worm jaws across the genera Platynereis, Glycera and Nereis. The square of the hardness scales with the inverse of the indentation depth, indicating a Nix-Gao size effect as known for crystalline metals. The limit hardness for the indentation depth going to infinity, amounting to 0.53 GPa, appears to be an invariant material property of the ion-spiked structural proteins likely used by all types of bristle worms. Such a metal-like biogenic material is a major source of bio-inspiration.


2019 ◽  
Vol 71 (4) ◽  
pp. 593-607
Author(s):  
Jinjuan Cheng ◽  
Zheming Wang ◽  
Xueping Gan ◽  
Qian Lei ◽  
Zhou Li ◽  
...  

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