Impact properties of intermetallic compounds

Kimura, Akihiko; Koya, A.; Morimura, Takao; Misawa, Toshihei

doi:10.1016/0921-5093(94)91010-3

Cited by 17 publications

(7 citation statements)

References 13 publications

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“…Utilization of compression testing, in contrast to tension, allows in-depth study of the work-hardening response of the various aluminides without the premature termination of the stress-strain response due to intersection with the failure envelope (George and Baker, 1998;Kimura et al, 1994;Oh et al, 1993;Yamaguchi and Inui, 1993). As will be shown in the next section, the strain-hardening response of polycrystalline intermetallics differs substantially from the general behavior of disordered metals and alloys shown in Figure 2 in two distinct ways.…”

mentioning

confidence: 99%

Strain Hardening

Gray¹,

Pollock²

2002

Intermetallic Compounds ‐ Principles and Practice

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mentioning

confidence: 99%

Strain Hardening

Gray¹,

Pollock²

2002

Intermetallic Compounds ‐ Principles and Practice

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“…[13][14][15] Tsuji et al 15) produced an ultrafine equiaxed grain structure by the accumulative roll bonding (ARB) process in a 0.041% P added IF steel and carried out the miniaturized Charpy impact tests. 16) They 15) found that the DBTT is successively decreased by the grain refinement but the upper shelf energy is reduced at the same. A similar result was reported by Jia et al 14) The reduced upper shelf energy by grain refinement has been reported in the thermo-mechanically processed steel 17) as well as the electrodeposited cobalt.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of Impact Toughness of 0.05% P Doped High Strength Steel through Formation of an Ultrafine Elongated Grain Structure

et al. 2010

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An ultrafine elongated grain (UFEG) structure with a strong ͗110͘//rolling direction (RD) fibre deformation texture was produced by warm calibre-rolling at 773 K in 1 200 MPa-class medium-carbon low-alloy steels with phosphorous (P) contents of 0.001 and 0.053 mass%. Charpy impact tests were performed at room temperature on the UFEG structure along with a conventional quenched and tempered (QT) structure. P segregation embrittlement completely disappeared in the UFEG structure. The UFEG structure exhibited the same high absorbed energy of 150 J regardless of P content, although the absorbed energy of the QT structure was significantly decreased from 93 J for 0.001 % P steel to 23 J for 0.053 % P steel due to occurrence of intergranular fracture. The high absorbed energy of 150 J for 0.053 % P-doped UFEG structure was believed to be due to both delamination fracture and fine/deep ductile dimples. The present results emphasized that the detrimental effects of P grain boundary segregation can be suppressed and the upper shelf energy can be increased through the formation of the UFEG structure.KEY WORDS: thermomechanical treatment; martensitic steel; toughness; delamination fracture; intergranular fracture; segregation embrittlement. gated grain (UFEG) structures with a strong ͗110͘// rolling direction (RD) deformation texture were obtained in high strength steel bars through the calibre-rolling of tempered martensite (tempforming) and the UFEG structures showed an increase in the upper shelf energy in addition to a significant decrease in the DBTT for cleavage fracture. Since elongated grain shape along the longitudinal direction of an impact specimen gives rise to much larger deflection angles than 60°when crack propagation along grain boundary takes place, 5) the UFEG structure is expected to suppress intergranular fracture markedly. Therefore, in the present study, we have tried to produce the UFEG structure to a Pdoped high strength steel in order to investigate whether it is possible to obtain both the suppression of intergranular fracture and the enhancement of upper shelf energy in a brittle high strength steel at a conventional QT condition. Peculiarities of the microstructure and the fracture behavior and their relation are discussed in some details. Experimental Material and Heat TreatmentTwo steels with the basic chemical compositions of 0.4% C, 0.25% Si, 0.73% Mn, 0.001% S, 1.0% Cr, 0.2% Mo, and P contents of 0.001 and 0.053% (all in mass %) were selected for the present study. Their chemical compositions are shown in Table 1, which are similar to that of a high strength JIS SCM 440 (AISI 4140) steel. Note that 0.053% P is more than twice as high as the typical P content of approximately 0.02% of a SCM 440 steel. Hence the 0.053% P steel was selected as a brittle steel.Two 100 kg ingots with different P contents were prepared by vacuum induction melting and casting. The ingots were homogenized at 1 473 K, and hot-rolled to plates with a thickness of 4 cm. Blocks of 12ϫ4ϫ4 cm 3 were cut out of the plates...

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“…The ARB process followed by annealing is carried out in the present investigation to provide the bulky samples having various UFG sizes. Because the ARB can only fabricate sheet materials having limited thickness, the miniaturized Charpy impact test 12,13) is carried out to measure the dynamic fracture toughness of the materials.…”

Section: Introductionmentioning

confidence: 99%

Toughness of Ultrafine Grained Ferritic Steels Fabricated by ARB and Annealing Process

et al. 2004

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A plain IF steel and a P-added IF steel having various ultrafine grain sizes from 0.24 to 11 mm were fabricated by the accumulative roll bonding (ARB) process followed by annealing. Dynamic fracture toughness of the ultrafine grained IF steels was investigated as a function of grain size by miniaturized Charpy impact test. The static strength of the IF steels significantly increased with decreasing the grain size, while the uniform elongation was limited in the ultrafine grained samples. A number of delamination appeared in the impact-tested specimens, especially in the ultrafine grained materials at low temperatures. It was concluded that the frequent delamination is not owing to insufficient roll-bonding in the ARB specimens but it is rather a characteristic feature of the ultrafine grained materials fabricated through heavy deformation. Because of the delamination, the absorbed energy in the impact test continuously decreased with decreasing the test temperature. On the other hand, an obvious change from the ductile fracture surface characterized by dimples into the brittle fracture surface mainly due to intergranular fracture was recognized at a certain low temperature. The ductile-brittle transition temperature determined from the microscopic fracture surfaces greatly decreased with decreasing the grain size, and finally no brittle fracture happened even at À190 C when the grain size was smaller than 5 mm or 2 mm in the plain IF steel or the P-added IF steel, respectively. It was concluded that the ultra-grain refinement is quite effective to improve the low-temperature toughness of ferritic steels and that it is possible to make phosphorus substantially harmless by grain refinement.

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Impact properties of intermetallic compounds

Cited by 17 publications

References 13 publications

Strain Hardening

Strain Hardening

Enhancement of Impact Toughness of 0.05% P Doped High Strength Steel through Formation of an Ultrafine Elongated Grain Structure

Toughness of Ultrafine Grained Ferritic Steels Fabricated by ARB and Annealing Process

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