Static and dynamic flexural strength of 99.5% alumina: Relation to surface roughness

Belenky, A.; Rittel, D.

doi:10.1016/j.mechmat.2012.07.003

Cited by 14 publications

(6 citation statements)

References 23 publications

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“…These microstructures observed were similar to those commonly reported (Ref 8,9). The reaction layer phase was characterized as Ti 3 (Cu+Al) 3 O, using EDX, in both D-96 AG (Fig. 9a, F) and in D-100 AG (Fig.…”

Section: Microstructure Of Brazed Jointssupporting

confidence: 89%

The Effect of Post-grinding Heat Treatment of Alumina and Ag-Cu-Ti Braze Preform Thickness on the Microstructure and Mechanical Properties of Alumina-to-Alumina-Brazed Joints

Kassam

Babu

Ludford

et al. 2016

J. of Materi Eng and Perform

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Alumina-to-alumina-brazed joints were formed using 96.0 and 99.7 wt.% Al 2 O 3 and TICUSIL Ò (68.8Ag-26.7Cu-4.5Ti wt.%) preforms of different thicknesses. Brazing was conducted in a vacuum of 1 3 10 25 mbar at 850°C for 10 minutes. Joint strengths were evaluated using four-point bend testing and were compared to flexural strengths of standard test bars. Post-grinding heat treatment, performed at 1550°C for 1 hour, did not affect the average surface roughness or grain size of either grades of alumina but affected their average flexural strengths with a small increase for 96.0 wt.% Al 2 O 3 and a small decrease for 99.7 wt.% Al 2 O 3 . As the TICUSIL Ò preform thickness was increased from 50 to 100 lm, the average strengths of both 96.0 and 99.7 wt.% Al 2 O 3 brazed joints improved. Joints made using 100-lm-thick TICUSIL Ò preforms predominantly consisted of Cu-Ti phases which formed due to excess Ti in the interlayers and non-uniform Ag-rich outflow. Brazed joints of 96.0 wt.% Al 2 O 3 made using 100-lm-thick TICUSIL Ò preforms achieved an average joint strength of 238 MPa with consistent failure in the ceramic.

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Section: Microstructure Of Brazed Jointssupporting

confidence: 89%

The Effect of Post-grinding Heat Treatment of Alumina and Ag-Cu-Ti Braze Preform Thickness on the Microstructure and Mechanical Properties of Alumina-to-Alumina-Brazed Joints

Kassam

Babu

Ludford

et al. 2016

J. of Materi Eng and Perform

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“…For each material, the R a results are similar for the rubble, the corner and the biaxial fracture surfaces, again supporting the potential link between fragments from ballistic and flexural tests. Other researchers have observed a similar lack of difference in fracture surfaces between alumina ceramics tested at different strain rates [28,29], but this information has not been previously quantified. Caution, however, is required when considering the rubble fragments due to the differences observed in Hexoloy SA fracture surfaces, which are discussed below.…”

Section: Fracture Surface Analysis Initial Observationsmentioning

confidence: 86%

Understanding the ballistic event: methodology and initial observations

et al. 2016

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The purpose of the study is to accelerate the development of ceramic materials for armour applications by substantially increasing the information obtained from a high-energy projectile impact event. This has been achieved by modifying an existing test configuration to incorporate a block of ballistic gel, attached to the strike face of a ceramic armour system, to capture fragments generated during the ballistic event such that their final positions are maintained. Three different materials, representative of the major classes of ceramics for armour applications, alumina, silicon carbide, and boron carbide, have been tested using this system. Ring-on-ring biaxial disc testing has also been carried out on the same materials. Qualitative analysis of the fracture surfaces using scanning electron microscopy and surface roughness quantification, via stereo imaging, has shown that the fracture surfaces of biaxial fragments and ballistic fragments recovered from the edges of the tile are indistinguishable. Although the alumina and boron carbide fragments generated from areas closer to the point of impact were also similar, the silicon carbide fragments showed an increase in porosity with respect to the fragments from further away and from biaxial testing. This porosity was found to result from the loss of a boron-rich second phase, which was widespread elsewhere in the material, although the relevance of this to ballistic performance needs further investigation. The technique developed in this work will help facilitate such studies.

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“…38,39 Previous studies have reported that the e and S of brittle materials such as Al 2 O 3 are improved with decreased surface roughness. 38,40 Cheng et al conducted a digital image correlation analysis and showed a recognizable stress concentration at the valleys of a rough surface, where the stress concentration was induced around the pores, reducing S and e. 41 In addition, the interaction between the pores and other defects, such as pores and cracks, can affect the stress concentration and risk of crack propagation. 42,43 Therefore, the increased roughness and porosity owing to hygrothermal degradation induce stress concentration and have a destructive effect on S and e. As the hygrothermal environment becomes more severe, the number of defects and their damage potential simultaneously increase, resulting in a more drastic decrease in S and e.…”

Section: Characterization Of the Hygrothermal Degradation Of Mechanic...mentioning

confidence: 99%

Study of mechanical degradation of freestanding ALD Al₂O₃ by a hygrothermal environment and a facile protective method for environmentally stable Al₂O₃: toward highly reliable wearable OLEDs

Lee¹,

Jeon²,

Oh³

et al. 2023

Mater. Horiz.

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Static and dynamic flexural strength of 99.5% alumina: Relation to surface roughness

Cited by 14 publications

References 23 publications

The Effect of Post-grinding Heat Treatment of Alumina and Ag-Cu-Ti Braze Preform Thickness on the Microstructure and Mechanical Properties of Alumina-to-Alumina-Brazed Joints

The Effect of Post-grinding Heat Treatment of Alumina and Ag-Cu-Ti Braze Preform Thickness on the Microstructure and Mechanical Properties of Alumina-to-Alumina-Brazed Joints

Understanding the ballistic event: methodology and initial observations

Study of mechanical degradation of freestanding ALD Al₂O₃ by a hygrothermal environment and a facile protective method for environmentally stable Al₂O₃: toward highly reliable wearable OLEDs

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Static and dynamic flexural strength of 99.5% alumina: Relation to surface roughness

Cited by 14 publications

References 23 publications

The Effect of Post-grinding Heat Treatment of Alumina and Ag-Cu-Ti Braze Preform Thickness on the Microstructure and Mechanical Properties of Alumina-to-Alumina-Brazed Joints

The Effect of Post-grinding Heat Treatment of Alumina and Ag-Cu-Ti Braze Preform Thickness on the Microstructure and Mechanical Properties of Alumina-to-Alumina-Brazed Joints

Understanding the ballistic event: methodology and initial observations

Study of mechanical degradation of freestanding ALD Al2O3 by a hygrothermal environment and a facile protective method for environmentally stable Al2O3: toward highly reliable wearable OLEDs

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Study of mechanical degradation of freestanding ALD Al₂O₃ by a hygrothermal environment and a facile protective method for environmentally stable Al₂O₃: toward highly reliable wearable OLEDs