Effect of grain size on the fracture toughness and strength of alloy AK4-1ch

Teleshov, V. V.; Shtovba, Yu. K.; Smolentsev, Vladislav; Sirotkina, O. M.

doi:10.1007/bf00741939

Cited by 3 publications

(3 citation statements)

References 2 publications

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“…However, for thick products under plane strain, fracture is usually controlled by coarse particles, and a recrystallized grain structure is preferable. Teleshov [26] studied the effect of grain size on fracture toughness and strength of AK4-1CH extrusion products. It was shown that the larger grain size products have higher fracture toughness than the smaller grain size products in L-T, T-L, and S-L directions, especially in the T-L direction.…”

Section: Discussionmentioning

confidence: 99%

Effect of Grain Refiner on Fracture Toughness of 7050 Ingot and Plate

Wang

Huang

et al. 2021

Materials

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In this paper, two types of grain refining alloys, Al-3Ti-0.15C and Al-5Ti-0.2B, were used to cast two types of 7050 rolling ingots. The effect of Al-3Ti-0.15C and Al-5Ti-0.2B grain refiners on fracture toughness in different directions for 7050 ingots after heat treatment and 7050-T7651 plates was investigated using optical electron microscopy (OEM) and scanning electron microscopy (SEM). Mechanical properties testing included both tensile and plane strain fracture toughness (KIC). The grain size was measured from the surface to the center of the 7050 ingots with two different grain refiners. The fracture surface was analyzed by SEM and energy dispersive spectrometer (EDS). The experiments showed the grain size from edge to center was reduced in 7050 ingots with both the TiC and TiB refiners, and the grain size was larger for ingots with the Al-3Ti-0.15C grain refiner at the same position. The tensile properties of 7050 ingots after heat treatment with Al-3Ti-0.15C grain refiner were 1–2 MPa lower than the ingot with the Al-5Ti-0.2B grain refiner. For the 7050-T7651 100 mm thick plate with the Al-3Ti-0.15C grain refiner, for the L direction, the tensile properties were lower by about 10~15 MPa; for the plate with the Al-3Ti-0.15C refiner than plate with Al-5Ti-0.2B refiner, for the LT direction, the tensile properties were lower by about 13–18 MPa; and for the ST direction, they were lower by about 8–10 MPa compared to that of Al-5Ti-0.2B refiner. The fracture toughness of the 7050-T7651 plate produced using the Al-3Ti-0.15C ingot was approximately 2–6 MPa · m higher than the plate produced from the Al-5Ti-0.2B ingot. Fractography of the failed fracture toughness specimens revealed that the path of crack propagation of the 7050 ingot after heat treatment produced from the Al-3Ti-0.15C grain refiner was more tortuous than in the ingot produced from the Al-5Ti-0.2B, which resulted in higher fracture toughness.

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Section: Discussionmentioning

confidence: 99%

Effect of Grain Refiner on Fracture Toughness of 7050 Ingot and Plate

Wang

Huang

et al. 2021

Materials

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“…This is because the 2XXX alloys have larger intermetallic compounds in their microstructure. Improvement in fracture toughness can be achieved by suitably and work of plastic deformation are larger for a coarse-grained structure leading to an increase of KIc [32]. This is also one of the reasons why there is not much improvement in fracture toughness of the alloy even after refining.…”

Section: Fracture Toughnessmentioning

confidence: 92%

“…In impact and fracture toughness tests, the alloy failed by a dimple mechanism. The fracto graphic studies did not reveal (a) the occurrence of intergranular fracture [32]. The type of fracture and the fracture path are shown in Fig.…”

Section: Fractographymentioning

confidence: 97%

A Study of the Fatigue, Impact and Fracture Toughness Characteristics of Electroslag Refined IS: 7670 Alloy

Sampath¹,

Dwarakadasa²

1993

Canadian Metallurgical Quarterly

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The nuclear, aerospace, naval and missile industries place emphasis on materials with high structural integrity and reliable performance so as to meet certain stringent requirements in service. Strength is not the only criterion for selection. Properties such as fatigue resistance, impact toughness and fracture toughness. are equally important. Electroslag refining (ESR) has been used widely and successfully over the years for improving the fatigue resistance, creep resistance, impact strength and fracture toughness of steels and alloy steels. But application of ESR to aluminium alloys is only a recent endeavour. A highstrength aircraft aluminium alloy IS: 7670 was therefore chosen for studies on the fatigue strength and the impact and fracture toughness. The results indicate that the fatigue resistance is considerably improved after refining and that the impact strength and fracture toughness of the refined alloy are comparable with that of the unrefined alloy.Resume-Les industries nucleaire, aerospatiale et navale s'interessent gran dement aux materiaux presentant une tres grande intetrite structurale ainsi qu'une performance fiable, afin de satisfaire certaines exigences rigoureuses en service. La resistance mecanique n'est pas Ie seul critere de selection. Des propeietes comme la resistance a la fatigue, la resistance a l'impact ainsi que la tenacite sont egalement importantes. L'affinement par electroslag (ESR) est un procede qui a ete couramment utilise avec succes dans Ie passe pour ameliorer la resistance a la fatigue et au fluage ainsi que la resistance a l'impact et la tenacite d'aciers et d'aciers allies. Par contre, l'application du ESR aux alIiages d'aluminium est uneffort relativement recent. Le IS: 7670, un alliage d'aluminium a haute resistance pour applications aeronautiques, a donc ete choisi pour les etudes de fatigue et de tenacite. Les resultats montrent que la resistance a la fatigue est considerablement amelioree apres ESR et que la resistance a l'impact et la tenacite de l'alliage affine sont comparables a celles de l'alliage non affine.

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Effect of grain size on the crack resistance of aluminum alloys

Rabinovich¹,

Markuskev²

1994

Met Sci Heat Treat

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669.715:620,17 Crack resistance is an important characteristic of the structural strength of materials. The reliability criteria for articles depend upon it, i.e., 'safe damage' and 'safe life.' The alloys were studied with recrystallized fine-grain (FG) and coarse-grain (CG) structures (Table 1). The coarse-grain size was about four times greater than that of the fine-gram size. Alloy V96ts in the CG condition had unrecrystallized strongly drawn-out grains with a developed substructure. Mechanical tests on the alloys were carried out under conditions of static, impact, and alternating loading.It is established that a change-over from a recrystallized coarse-grain structure to a fine-grain structure for alloys AMg6 and AK4-1 is accompanied .by a small increase in strength properties (within the limits of 2-5%) ( Table 2) which apparently is Perch in nature. To a comparatively large extent (by 9-30%) there is an increase in ductility characteristics (relative elongation and reduction of area) which is caused by greater uniformity of macro-and microplastic strain [1].Analysis of fractures of longitudinal specimens after static failure showed that the failure of alloys AMg6 and AK4-1 with both coarse-and fine-grain structures is ductile in nature: the fracture is mainly transcrystalline with predominant pitted failure (Fig. 1). Areas are observed with transcrystalline quasicleavage. In fine-grain alloys the size of these areas is markedly smaller. The difference in the nature of failure involves the fact that the proportion of intercrystalline failure for alloy AMg6 was 10 _+ 2 %, but for alloy AK4-1 it was 22 + 5 %, and it was the same in the coarse-and fine-grain conditions. The physical prerequisite for a change in the nature of failure is presence at grain boundaries of alloy AK4-1 of a large number of excess phase particles and presence of boundary zones free from precipitates missing for alloy AMg6.From the results of static tensile tests on longitudinal cylindrical specimens with a circular notch it is established that with a radius at the notch tip r = 0.05 mm fine-grain alloy AMg6 has less failure strength than coarse-grain alloy. With a less sharp notch (r = 0.3 ram) the effect of grain size on o F is not detected ( Table 1). The considerable sensitivity of fine-grain alloy to notch sharpness points to a reduction in crack growth resistance. With grain refinement the work for failure of smooth specimens (y) increases (Table 2). This may only be explained by an increase in the resistance to crack generation which is more significant than a reduction in growth resistance. These data were confirmed by' the results of testing in eccentric tension of smooth specimens with a side notch (by the Kahn method [2]) (Table 2), With a change-over from coarse-grain to a fine-grain structure the specific work for failure a 1 of specimens of alloy AMg6 increases which correlates with a change in y. An increase in these characteristics with grainInstitute of Metal Superplasticity Problems, Russian Academy of Sciences...

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Effect of grain size on the fracture toughness and strength of alloy AK4-1ch

Cited by 3 publications

References 2 publications

Effect of Grain Refiner on Fracture Toughness of 7050 Ingot and Plate

Effect of Grain Refiner on Fracture Toughness of 7050 Ingot and Plate

A Study of the Fatigue, Impact and Fracture Toughness Characteristics of Electroslag Refined IS: 7670 Alloy

Effect of grain size on the crack resistance of aluminum alloys

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