Damage and failure analyses of 3D4d braided composite shafts under torsional load and the effects of braid processing parameters on their torsional properties

2021 ◽  
Vol 42 (4) ◽  
pp. 1912-1944
Author(s):  
Ya Wang ◽  
Zhen‐Guo Liu ◽  
Yun‐Peng Yi ◽  
Yu‐Chen Wei ◽  
Zhi‐jian Li ◽  
...  
Keyword(s):  
Processing Parameters ◽  
Braided Composite ◽  
Damage And Failure ◽  
Torsional Load ◽  
Torsional Properties

Failure analysis of three-dimensional braided composite tubes under torsional load: Experimental study

2017 ◽  
Vol 36 (12) ◽  
pp. 878-888 ◽  
Author(s):  
Xiaopei Wang ◽  
Deng’an Cai ◽  
Chao Li ◽  
Fangzhou Lu ◽  
Yu Wang ◽  
...  
Keyword(s):  
Experimental Study ◽  
Failure Modes ◽  
Shear Failure ◽  
Three Dimensional ◽  
Damage Mechanism ◽  
Test Device ◽  
Composite Tubes ◽  
Torsional Strength ◽  
Braided Composite ◽  
Torsional Load

An experimental study on the effects of braided processes on the torsional strength, torsional modulus and failure modes of the three-dimensional braided composite tubes are presented. Based on the movement of carries, the yarn traces of three-dimensional braided composite tubes are analyzed systematically. Four different three-dimensional braided composite tubes are formed by resin transfer molding, and a number of torsional tests are performed respectively using a special test device. It is found that the torsional strength of three-dimensional five-directional braided composite tubes is higher than others, while the torsional modulus of three-dimensional multi-layer wrapping braided composite tubes is the highest. Furthermore, the damage behaviors of 3D braided composite tubes are significantly influenced by braiding process. One focus is to evaluate the damage mechanism of three-dimensional braided composite tubes by cutting the specimens and using scanning electron microscopy. Under torsional load, three-dimensional five-directional braided composite tubes and three-dimensional surface-core five-directional braided composite tubes are fractured in compression and shear failure, while three-dimensional multi-layer wrapping braided composite tubes and three-dimensional seven-directional braided composite tubes are split open in tensile and shear failure.

Microstructural Variations in Melt-Spun Rapidly Solidified Ribbons

1985 ◽  
Vol 43 ◽  
pp. 54-55
Author(s):  
L. A. Bendersky ◽  
W. J. Boettinger
Keyword(s):  
Solid State ◽  
Processing Parameters ◽  
Heat Extraction ◽  
Solid State Reactions ◽  
Careful Examination ◽  
Ion Milling ◽  
Melt Spun ◽  
Wheel Side ◽  
Rapidly Solidified ◽  
Heat Extraction Rate

Rapid solidification produces a wide variety of sub-micron scale microstructure. Generally, the microstructure depends on the imposed melt undercooling and heat extraction rate. The microstructure can vary strongly not only due to processing parameters changes but also during the process itself, as a result of recalescence. Hence, careful examination of different locations in rapidly solidified products should be performed. Additionally, post-solidification solid-state reactions can alter the microstructure.The objective of the present work is to demonstrate the strong microstructural changes in different regions of melt-spun ribbon for three different alloys. The locations of the analyzed structures were near the wheel side (W) and near the center (C) of the ribbons. The TEM specimens were prepared by selective electropolishing or ion milling.

Surface Modification and its Influence on the Microstructure and Creep Resistance of Nickel Based Superalloy René 77 / Modyfikacja Powierzchniowa Oraz Jej Wpływ Na Mikrostrukture I Wytrzymałosc Na Pełzanie Odlewów Z Nadstopu Niklu Ren´E 77

2013 ◽  
Vol 58 (1) ◽  
pp. 95-98 ◽  
Author(s):  
M. Zielinska ◽  
J. Sieniawski
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Surface Modification ◽  
Turbine Blades ◽  
Processing Parameters ◽  
Grain Structure ◽  
Creep Tests ◽  
Cobalt Aluminate ◽  
Nickel Based Superalloy ◽  
Average Grain Size

Superalloy René 77 is very wide used for turbine blades, turbine disks of aircraft engines which work up to 1050°C. These elements are generally produced by the investment casting method. Turbine blades produced by conventional precision casting methods have coarse and inhomogeneous grain structure. Such a material often does not fulfil basic requirements, which concern mechanical properties for the stuff used in aeronautical engineering. The incorporation of controlled grain size improved mechanical properties. This control of grain size in the casting operation was accomplished by the control of processing parameters such as casting temperature, mould preheating temperature, and the use of grain nucleates in the face of the mould. For nickel and cobalt based superalloys, it was found that cobalt aluminate (CoAl2O4) has the best nucleating effect. The objective of this work was to determine the influence of the inoculant’s content (cobalt aluminate) in the surface layer of the ceramic mould on the microstructure and mechanical properties at high temperature of nickel based superalloy René 77. For this purpose, the ceramic moulds were made with different concentration of cobalt aluminate in the primary slurry was from 0 to 10% mass. in zirconium flour. Stepped and cylindrical samples were casted for microstructure and mechanical examinations. The average grain size of the matrix ( phase), was determined on the stepped samples. The influence of surface modification on the grain size of up to section thickness was considered. The microstructure investigations with the use of light microscopy and scanning electron microscopy (SEM) enable to examine the influence of the surface modification on the morphology of ’ phase and carbides precipitations. Verification of the influence of CoAl2O4 on the mechanical properties of castings were investigated on the basis of results obtained form creep tests.

A geometallurgical characterization study of the Crystalkop Reef at the Great Noligwa Mine, Klerksdorp Goldfield, South Africa

2017 ◽  
Vol 120 (3) ◽  
pp. 303-322
Author(s):  
D. Pienaar ◽  
B.M. Guy ◽  
C. Pienaar ◽  
K.S. Viljoen
Keyword(s):  
South Africa ◽  
Treatment Plant ◽  
Processing Parameters ◽  
Processing Plant ◽  
Small Contribution ◽  
Gold Cyanide ◽  
Three Samples ◽  
Characterization Study ◽  
Different Sources

Abstract Mineralogical and textural variability of ores from different sources commonly leads to processing inefficiencies, particularly when a processing plant is designed to treat ore from a single source (i.e. ore of a relatively uniform composition). The bulk of the Witwatersrand ore in the Klerksdorp goldfield, processed at the AngloGold Ashanti Great Noligwa treatment plant, is derived from the Vaal Reef (>90%), with a comparatively small contribution obtained from the Crystalkop Reef (or C-Reef). Despite the uneven contribution, it is of critical importance to ensure that the processing parameters are optimized for the treatment of both the Vaal and C-Reefs. This paper serves to document the results of a geometallurgical study of the C-Reef at the Great Noligwa gold mine in the Klerksdorp goldfield of South Africa, with the primary aim of assessing the suitability of the processing parameters that are in use at the Great Noligwa plant. The paper also draws comparisons between the C-Reef and the Vaal Reef A-facies (Vaal Reef) and attempts to explain minor differences in the recovery of gold and uranium from these two sources. Three samples of the C-Reef were collected in-situ from the underground operations at Great Noligwa mine for mineralogical analyses and metallurgical tests. Laboratory-scale leach tests for gold (cyanide) and uranium (sulphuric acid) were carried out using dissolution conditions similar to that in use at the Great Noligwa plant, followed by further diagnostic leaching in the case of gold. The gold in the ore was found to be readily leachable with recoveries ranging from 95% to 97% (as opposed to 89% to 93% for the Vaal Reef). Additional recoveries were achieved in the presence of excess cyanide (96% to 98%). The recovery of uranium varied between 72% and 76% (as opposed to 30% to 64% for the Vaal Reef), which is substantially higher than predicted, given the amount of brannerite in the ore, which is generally regarded as refractory. Thus, the higher uranium recoveries from the C-Reef imply that a proportion of the uranium was recovered by the partial dissolution of brannerite. As the Vaal Reef contain high amounts of chlorite (3% to 8%), which is an important acid consumer, it is considered likely that this could have reduced the effectiveness of the H2SO4 leach in the case of the ore of the Vaal Reef. Since the gold and uranium recoveries from the C-Reef were higher than the recoveries from the Vaal Reef, the results demonstrate that the processing parameters used for treatment of the Vaal Reef are equally suited to the treatment of the C-Reef. Moreover, small processing modifications, such as increased milling and leach retention times, may well increase the recovery of gold (particularly when e.g. coarse gold, or unexposed gold, is present).

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