Excellent Resistance to Hydrogen Embrittlement of High-Strength Copper-Based Alloy

Author(s):  
Yuhei Ogawa ◽  
Junichiro Yamabe ◽  
Hisao Matsunaga ◽  
Saburo Matsuoka

In order to develop more energy-efficient and safer, hydrogen pre-cooling systems destined for use in hydrogen refueling stations, a metallic material must first be researched and found to possess three excellent material properties: high strength, high thermal conductivity and low susceptibility to hydrogen embrittlement (HE). This study investigated the hydrogen compatibility of a beryllium-copper alloy 25 (UNS-C17200), fabricated by a solution annealing at 1053 K and via subsequent aging treatment at 588 K. After these thermal processes, the tensile strength exceeded 1200 MPa, due to the precipitation of nano-sized CuBe compounds (γ’ phase). Slow strain rate tensile (SSRT) and tension-compression fatigue tests were performed using this material, in addition to fatigue crack growth and fracture toughness tests, in laboratory air and in gaseous hydrogen with a pressure of 115 MPa at room temperature. After the SSRT test, the material showed no hydrogen-induced degradation of strength or ductility and, surprisingly, there was also no degradation of fatigue resistance or fracture toughness values in high-pressure gaseous hydrogen. Specifically, it was revealed that the material demonstrated an excellent HE resistance, despite having such a high tensile strength.

Alloy Digest ◽  
1993 ◽  
Vol 42 (2) ◽  

Abstract LESCALLOY 300M VAC ARC is a low-alloy steel with an excellent combination of high hardenability and high strength coupled with good ductility and good toughness. Its tensile strength ranges from 280,000 to 300,000 psi. It is produced by the vacuum consumable electrode melting process to provide optimum cleanliness and preferred ingot structure. Its applications include aircraft components, pressure vessels and fasteners. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: SA-321. Producer or source: Latrobe Steel Company. Originally published March 1976, revised February 1993.


Alloy Digest ◽  
1998 ◽  
Vol 47 (5) ◽  

Abstract Inland DuraSpring is a high-strength microalloyed spring steel for use in high stress coil springs for automobile and light truck suspension systems. This bar product offers significant improvements in tensile strength, fatigue properties, and fracture toughness compared to conventional spring steels. This datasheet provides information on composition, hardness, and tensile properties as well asfracture toughness and fatigue. Filing Code: SA-496. Producer or source: Ispat Inland Inc.


Alloy Digest ◽  
1962 ◽  
Vol 11 (5) ◽  

Abstract Crucible D6 is a low alloy ultra-high strength steel developed for aircraft-missile applications and primarily designed for use in the 260,000-290,000 psi tensile strength range. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness, creep, and fatigue. It also includes information on low temperature performance as well as forming, heat treating, machining, and joining. Filing Code: SA-129. Producer or source: Crucible Steel Company of America.


Proceedings ◽  
2018 ◽  
Vol 2 (23) ◽  
pp. 1417
Author(s):  
Guillermo Álvarez Díaz ◽  
Tomás Eduardo García Suárez ◽  
Cristina. Rodríguez González ◽  
Francisco Javier Belzunce Varela

The aim of this work is to study the effect of the displacement rate on the hydrogen embrittlement of two different structural steels grades used in energetic applications. With this purpose, samples were pre-charged with gaseous hydrogen at 19.5 MPa and 450 °C for 21 h. Then, fracture tests of the pre-charged specimens were performed, using different displacement rates. It is showed that the lower is the displacement rate and the largest is the steel strength, the strongest is the reduction of the fracture toughness due to the presence of internal hydrogen.


2020 ◽  
Vol 10 (7) ◽  
pp. 1020-1031
Author(s):  
Zehua Yan ◽  
Yandong Yu ◽  
Yanchao Sang ◽  
Yiming Yao ◽  
Jiahao Qian

Magnesium alloy plates can be strengthened by rolling, however, it is easy to crack or even break when the reduction of Mg–RE alloys is too large. Herein, the strengthening mechanical of the Mg–9Gd–3Nd–1Sn–1Zn– 0.6Zr alloy under different treatment conditions were investigated after hot-rolling to 80% reduction in thickness (0.8 mm) by multi-step methods. Furthermore, the rolled alloy by aging strengthening are explored. The results show that the hot-rolled alloy with 80% reduction are basically composed of dynamically recrystallized grains with the size of about 60 m, improving the mechanical properties significantly. The precipitates within grains undergo SSSS→ β″ → β′ phase transformation with the aging treatment up to 200 °C. Fine β″ precipitates were found in the grains of the rolled alloy under aged time (2 h), while β″ precipitates changed into β′ phase when the aging time was extended to 32 h. The base phase which is perpendicular to phase was precipitated in the alloy in longer aging time (96 h). In addition, the thickness of precipitates and precipitation-free zone (PFZ) at the grain boundary gradually increased as the time went on. Meanwhile, the discontinuous equilibrium phases at the grain boundary are gradually become continuous. The ultimate tensile strength and hardness were reached to 431.14 MPa, 105.9 HV at peak-aging, in addition, the elongation is reached to 3.11%, respectively. The formation of crack sources is due to the stress concentration between the brittle PFZ and the magnesium matrix, which leads to the decrease of ductility.


1990 ◽  
Vol 34 ◽  
pp. 719-727 ◽  
Author(s):  
Sumio Tanaka ◽  
Yukio Hirose ◽  
Keisuke Tanaka

The residual stress left on the fracture surface is one of the important parameters in X-ray fractographic study. It has been used to analyze fracture mechanisms in fracture toughness and fatigue tests especially of high strength steels.In this paper, X-ray fractography was applied to brittle fracture of alumina (Al2O3) and zirconia (ZΓO2) ceramics.


2010 ◽  
Vol 17 (01) ◽  
pp. 93-97 ◽  
Author(s):  
HOON CHO ◽  
BYOUNG-SOO LEE ◽  
HYUNG-HO JO

The effect of thermal heat treatment on the mechanical and electrical properties of Cu–Ag alloys was investigated. The homogenization heat treatment leads to an increase in tensile strength and a decrease in electrical conductivity due to dissolution of Ag into copper matrix. Also, it is shown that electrical conductivity of as-cast Cu–Ag alloys decreases with increasing Ag content. In contrast, the aging heat treatment gives rise to increase both the tensile strength and electrical conductivity because the Ag solute diffuses out from copper matrix during aging heat treatment. Therefore, it can be mentioned that the electrical conductivity of Cu–Ag alloys depends on Ag solute in copper matrix. Also, aging treatment is favorable to acquire high strength and high electrical conductivity.


2011 ◽  
Vol 462-463 ◽  
pp. 1361-1366 ◽  
Author(s):  
Bo Ming Zhang ◽  
Yu Fen Wu

For the sake of the carbon filaments’ fracture toughness, using the focused ion beam (FIB) to etch the carbon fibers and got different tensile strength, and all specimens were stretched on an Instron-type filaments testing machine and got the samples’ tensile strength, The crack-to-mirror size ratio was assumed as a constant, In virtue of Griffith fracture theory, Fracture toughness (KΙC) of representative high-strength type PAN (polyacrylonitrile)-based carbon fibers, Torayca T300 and T800, were estimated to be 1MPam1/2 from the tensile strength vs. fracture mirror size relation.


2010 ◽  
Vol 667-669 ◽  
pp. 421-426 ◽  
Author(s):  
M.X. Yang ◽  
Gang Yang ◽  
Zheng Dong Liu ◽  
Cun Yu Wang ◽  
C.X. Huang

An 18Ni (C-250) maraging steel was successfully processed by equal channel angular pressing (ECAP) for a single pass at room temperature. Microstructural observations showed that the martensite laths of 18Ni maraging steel were elongated to more narrow bands with a width of 100-200 nm after ECAP deformation. After ageing treatment, many nano-sized precipitates distributed uniformly within the refined martensite lathes. In comparison with the tensile strength (1940 MPa) of general used steel (solution + aging treatment), the tensile strength of the sample processed by ECAP and subsequent aging treatment was enhanced for more than 100 MPa (above 2050 MPa). The enhancement of tensile properties was attributed to microstructural refinement and uniformly distributed nano-precipitates.


Author(s):  
Junichiro Yamabe ◽  
Hisatake Itoga ◽  
Tohru Awane ◽  
Hisao Matsunaga ◽  
Shigeru Hamada ◽  
...  

Pressure cycle tests were performed on two types of Cr-Mo steel pressure vessels with inner diameters of 306 mm and 210 mm and notches machined on their inside under hydrogen-gas pressures, varied between 0.6 and 45 MPa at room temperature. One of the Cr-Mo steels had a fine microstructure with tensile strength of 828 MPa, while the other had a coarse microstructure with tensile strength of 947 MPa. Fatigue-crack growth (FCG) and fracture-toughness tests of the Cr-Mo steels were also carried out in gaseous hydrogen. The Cr-Mo steels showed accelerated FCG rates in gaseous hydrogen compared to ambient air with an upper bound corresponding to an approximately 30-times higher FCG rate. Furthermore, in gaseous hydrogen, the fracture toughness of the Cr-Mo steel with coarse microstructure was significantly smaller than that of the steel with fine microstructure. Four pressure vessels were tested; then, all of the pressure vessels failed by leak-before-break (LBB). Based on the fracture-mechanics approach, the LBB failure of one pressure vessel could not be estimated by using the fracture toughness in gaseous hydrogen. The fatigue lives could be estimated by using the upper bound of the accelerated FCG rates in gaseous hydrogen.


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