Paints and varnishes. Bend test (conical mandrel)

ABSTRACTThe results of our initial efforts at measuring the fracture strengths of grain boundaries In Ni3Al using a miniaturized disk-bend test are presented. The samples tested were 3 mm in diameter and between 150 and 300 μm thick. An Ingot of directlonally-solidlfled, boron-free Ni3Al containing 24% Al was annealed between 1300 and 1350 °C to induce grain growth, producing many grain boundaries In excess of 1.5 mm in length. Specimens were cut from these In such a way that one long grain boundary was located near a diameter of the specimen. The relative orientations of the grains on either side of the boundary were determined from electron channeling patterns. Low-angle boundaries are so strong they do not fracture; Instead the samples deform In a completely ductile manner. High-angle boundaries always fracture, but only after considerable plastic deformation of the two grains flanking them. Fracture is Indicated by a load drop in the load vs. displacement curves. A method involving extrapolation of the elastic portion of these curves to the displacement at fracture is used to estimate the fracture stresses. This procedure yields consistent values of the fracture strengths of high-angle boundaries. The measured stresses are large (∼2 to 3 GPa), but considerably smaller than those required for the fracture of special boundaries, as predicted by computer simulations. No correlation was found between the fracture stresses or loads and the geometry of the high-angle boundaries, many of which are close to, but deviate from, coincident site lattice orientations.

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Evaluation of fatigue resistance of asphalt mixes using Four Point Beam Fatigue and Semi-Circular Bend test methods

Computer Methods and Recent Advances in Geomechanics ◽

10.1201/b17435-77 ◽

2014 ◽

pp. 459-464

Author(s):

M Barman ◽

R Ghabchi ◽

D Singh ◽

M Zaman ◽

S Commuri ◽

...

Keyword(s):

Fatigue Resistance ◽

Test Methods ◽

Bend Test ◽

Asphalt Mixes

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The Effect of AC (alternating current) and DC (direct current) on Bend Testing Results of Low Carbon Steel Welding Joints

Teknomekanik ◽

10.24036/teknomekanik.v3i2.6272 ◽

2020 ◽

Vol 3 (2) ◽

pp. 56-61

Author(s):

Zetri Firmanda ◽

Abdul Aziz ◽

Bulkia Rahim

Keyword(s):

Carbon Steel ◽

Direct Current ◽

Low Carbon Steel ◽

Welding Process ◽

Alternating Current ◽

Bend Test ◽

Open Crack ◽

Low Carbon ◽

Bend Testing ◽

Welding Joints

The purpose of this study was to determine the effect of alternating current (AC) and direct current (DC) on the bend testing results of low carbon steel welding joints. The results of this study are expected to determine the cracks that occur from the root bend and face bend testings in the AC and DC welding process. This study used experimental method, where the research was done by giving AC and direct polarity DC (DC-) SMAW welding treatments. The material used in this research was low carbon steel plate DIN 17100 Grade ST 44, thickness 10 with E7016 electrode type. The process of welding joints used a single V seam, strong current of 90A, and the welding position of 1G. The testing of welding joints was carried out by bend testing using the standard acceptance of AWS D1.1 root bend and face bend testing results. The results of the bend testing showed that the AC welding root bend test specimen held no cracks while the DC welding root bend test held cracks with incompelete penetration and open crack defects. On the contrary, the AC welding face bend test had open crack defects and in the DC welding face bend test was found a crack. Thus, there was a difference in the crack resistance of the welding joint from the types of current used through the root bend test and face bend test. Therefore, it can be summarized that AC welding is better for root welding and DC welding is good for capping welding.

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