Nanoceramic composites with duplex microstructure break the strength-toughness tradeoff

2020 ◽  
Vol 58 ◽  
pp. 1-9 ◽  
Author(s):  
Ji Zou ◽  
Hai-Bin Ma ◽  
Jing-Jing Liu ◽  
Wei-Min Wang ◽  
Guo-Jun Zhang ◽  
...  
Keyword(s):  
Duplex Microstructure

NAS 64

Alloy Digest ◽  
2010 ◽  
Vol 59 (8) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Physical Properties ◽  
Stress Corrosion ◽  
Duplex Stainless Steel ◽  
Stress Corrosion Cracking ◽  
Crevice Corrosion ◽  
Heat Treating ◽  
Duplex Microstructure ◽  
Resistance To Stress

Abstract NAS 64 is a duplex stainless steel with molybdenum for pitting and crevice corrosion resistance and a duplex microstructure for resistance to stress-corrosion cracking. 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, and joining. Filing Code: SS-1072. Producer or source: Nippon Yakin Kogyo Company Ltd.

NAS 74N

Alloy Digest ◽  
2010 ◽  
Vol 59 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
Crevice Corrosion ◽  
Heat Treating ◽  
Super Duplex Stainless Steel ◽  
Duplex Microstructure ◽  
Temperature Performance ◽  
Resistance To Stress ◽  
Very High

Abstract NAS 74N is a super duplex stainless steel with very high molybdenum for pitting and crevice corrosion resistance and a duplex microstructure for resistance to stress-corrosion cracking. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, and joining. Filing Code: SS-1070. Producer or source: Nippon Yakin Kogyo Company Ltd.

AVESTA 2205 CODE PLUS TWO

Alloy Digest ◽  
1993 ◽  
Vol 42 (3) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Stress Corrosion ◽  
Heat Exchangers ◽  
High Strength ◽  
Heat Treating ◽  
Pressure Vessels ◽  
General Corrosion ◽  
Duplex Microstructure ◽  
Good Resistance ◽  
Desalination Plants

Abstract AVESTA 2205 is a ferritic-austenitic duplex stainless steel. It resists stress-corrosion cracking very well and has good pitting and general corrosion resistance. Its high strength and stress-corrosion resisting characteristics are a reflection of its duplex microstructure. Its uses include heat exchangers, desalination plants, and pressure vessels that need good resistance to corrosion. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-472. Producer or source: Avesta Sheffield Inc. Originally published July 1986, revised March 1993.

On the role of mechanical twinning in creep of a near-γ TiAl-alloy with duplex microstructure

1998 ◽  
Vol 39 (8) ◽  
pp. 1023-1029 ◽  
Author(s):  
Birgit Skrotzki ◽  
Mahinur Ünal ◽  
Gunther Eggeler
Keyword(s):  
Tial Alloy ◽  
Mechanical Twinning ◽  
Duplex Microstructure

scholarly journals Influence of the Alkaline Reserve of Chloride-Contaminated Mortars on the 6-Year Corrosion Behavior of Corrugated UNS S32304 and S32001 Stainless Steels

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 686 ◽  
Author(s):  
Asunción Bautista ◽  
Francisco Velasco ◽  
Manuel Torres-Carrasco
Keyword(s):  
Corrosion Behavior ◽  
Stainless Steels ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Duplex Microstructure ◽  
Testing Period ◽  
Alkaline Reserve ◽  
Eis Measurements ◽  
High Chloride ◽  
Chloride Concentrations

The durability of two lean corrugated duplex stainless steel (UNS S32304 and S32001) bars manufactured for concrete reinforcement was studied in four different corrosive conditions. These duplex stainless steels are more economical than the most traditional, well-known duplex grade steels (UNS S32205). The research was carried out in mortar samples for six years. In half of the samples, the alkaline reserve had been previously decreased, and their pH was slightly below 12, while in the other half, the pH close to the bars remained as-manufactured. Moreover, there were samples with modified and non-modified alkaline reserve where chlorides had been previously added to the mortar which were exposed to high relative humidity. In other samples—which were partially immersed in 3.5% NaCl—the chlorides entered through the mortar by natural diffusion. The electrochemical behavior of the reinforcements in these conditions was periodically monitored through corrosion potential (Ecorr) and electrochemical impedance spectroscopy (EIS) measurements during the whole testing period. The samples were anodically polarized at the end of the exposure. The results prove that the decrease in the alkaline reserve of the mortars can affect the corrosion behavior of the studied lean duplex in environments with high chloride concentrations. The duplex microstructure of the reinforcements makes it so that the corrosion proceeds by selective attack of the phases.

Elemental Segregation and O-Phase Formation in a Gamma-TiAl Alloy

2018 ◽  
Vol 941 ◽  
pp. 741-746 ◽  
Author(s):  
Heike Gabrisch ◽  
Tobias Krekeler ◽  
Uwe Lorenz ◽  
Marcus Willi Rackel ◽  
Martin Ritter ◽  
...  
Keyword(s):  
Tial Alloy ◽  
Titanium Aluminides ◽  
Orthorhombic Phase ◽  
Aircraft Engines ◽  
Duplex Microstructure ◽  
Two Phase ◽  
Chemical Homogeneity ◽  
Phase Form ◽  
Tial Alloys ◽  
O Phase

Titanium aluminides based on the L10 ordered g-phase are promising structural light-weight materials for applications in aircraft engines. Typical compositions for γ-TiAl alloys lie in the range Ti-(44-48)Al (at.-%). For high creep resistance, a two-phase microstructure based on lamellar (α2+γ)-colonies is desirable that may be tuned towards better ductility by introducing pure γ-grains (near lamellar or duplex microstructure).γ-TiAl alloys are often alloyed with niobium for increased oxidation resistance and improved mechanical properties. HEXRD and TEM studies of the alloy Ti-42Al-8.5Nb revealed that the orthorhombic O-phase forms during annealing at 500-650°C. This orthorhombic phase has been known in Nb-rich, Al-lean, α2-based Ti-aluminides since the late 1980ies (Nb> 12.5 at.-%, Al< 31 at.-%) but the finding in γ-based alloys is new.TEM imaging showed that the O-phase is located within α2 lamellae of lamellar (α2+γ)-colonies. O-phase domains and α2 phase form small columnar crystallites based in the α2/γ interface. The columnar crystallites grow parallel to the [0001] direction of the α2 phase and appear as facets when observed along this direction. The evolution of domains and facets with annealing time and the chemical homogeneity of the phases are investigated.The results of STEM imaging show that O-phase domains form during annealing at 550 °C for 8hours or 168 hours. After 168 hours of annealing Nb segregations are observed by EDX mapping within O-phase domains. In comparison, no segregation of niobium is detected after 8 hours of annealing.

scholarly journals Influence of Microstructural Morphology on Hydrogen Embrittlement in a Medium-Mn Steel Fe-12Mn-3Al-0.05C

Metals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 929 ◽  
Author(s):  
Xiao Shen ◽  
Wenwen Song ◽  
Simon Sevsek ◽  
Yan Ma ◽  
Claas Hüter ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
The Other ◽  
Duplex Microstructure ◽  
Ultrafine Grained ◽  
Medium Mn Steel ◽  
Microstructural Morphology ◽  
Cold Rolled ◽  
Mixed Microstructure ◽  
Mn Steel

The ultrafine-grained (UFG) duplex microstructure of medium-Mn steel consists of a considerable amount of austenite and ferrite/martensite, achieving an extraordinary balance of mechanical properties and alloying cost. In the present work, two heat treatment routes were performed on a cold-rolled medium-Mn steel Fe-12Mn-3Al-0.05C (wt.%) to achieve comparable mechanical properties with different microstructural morphologies. One heat treatment was merely austenite-reverted-transformation (ART) annealing and the other one was a successive combination of austenitization (AUS) and ART annealing. The distinct responses to hydrogen ingression were characterized and discussed. The UFG martensite colonies produced by the AUS + ART process were found to be detrimental to ductility regardless of the amount of hydrogen, which is likely attributed to the reduced lattice bonding strength according to the H-enhanced decohesion (HEDE) mechanism. With an increase in the hydrogen amount, the mixed microstructure (granular + lamellar) in the ART specimen revealed a clear embrittlement transition with the possible contribution of HEDE and H-enhanced localized plasticity (HELP) mechanisms.

Microstructure-Aided Analysis of Fatigue Thresholds in Duplex Stainless Steel

2007 ◽  
Vol 567-568 ◽  
pp. 101-104 ◽  
Author(s):  
Jaroslav Pokluda ◽  
Tomáš Podrábský ◽  
Karel Slámečka ◽  
Simona Hutařová ◽  
Guo Cai Chai
Keyword(s):  
Fatigue Cracks ◽  
Fatigue Threshold ◽  
Threshold Region ◽  
Threshold Values ◽  
Duplex Microstructure ◽  
Martensitic Steels ◽  
High Fatigue ◽  
Crack Paths ◽  
Plasticity Induced Crack Closure ◽  
Good Agreement

High fatigue threshold values of duplex ferritic-martensitic steels are interpreted by using a unified model of roughness- and plasticity induced crack closure. Complex metallographical and fractographical analysis was performed in order to obtain characteristics of tortuous crack paths produced by crack deflection and branching mainly at austenite/ferrite interfaces. Calculated values of effective thresholds are in a good agreement with experimental data. The total level of extrinsic toughening (closure + shielding) induced by the duplex microstructure was determined to be as much as 70% of measured fatigue threshold values. This is the main reason for the high resistance to propagation of long fatigue cracks in the near-threshold region.

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