Microstructure and mechanical properties of different keratinous horns

Animal horns play an important role during intraspecific combat. This work investigates the microstructure and mechanical properties of horns from four representative ruminant species: the bighorn sheep ( Ovis canadensis ), domestic sheep ( Ovis aries ), mountain goat ( Oreamnos americanus ) and pronghorn ( Antilocapra americana ), aiming to understand the relation between evolved microstructures and mechanical properties. Microstructural similarity is found where disc-shaped keratin cells attach edge-to-edge along the growth direction of the horn core (longitudinal direction) forming a lamella; multiple lamellae are layered face to face along the impact direction (radial direction, perpendicular to horn core growth direction), forming a wavy pattern surrounding a common feature, the tubules. Differences among species include the number and shape of the tubules, the orientation of aligned lamellae and the shape of keratin cells. Water absorption tests reveal that the pronghorn horn has the largest water-absorbing ability due to the presence of nanopores in the keratin cells. The loading direction (compressive and tensile) and level of hydration vary among the horns from different species. The differences in mechanical properties among species may relate to their different fighting behaviours: high stiffness and strength in mountain goat to support the forces during stabbing; high tensile strength in pronghorn for interlocked pulling; impact energy absorption properties in domestic and bighorn sheep to protect the skull during butting. These design rules based on evolutionary modifications among species can be applied in synthetic materials to meet different mechanical requirements.

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Process Design Strategies for Producing Heavy Section Steel with Improved Quality

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.652-654.988 ◽

2013 ◽

Vol 652-654 ◽

pp. 988-991

Author(s):

Jing Wei Zhao ◽

Zheng Yi Jiang ◽

Dong Bin Wei ◽

Chong Soo Lee

Keyword(s):

Mechanical Properties ◽

Chemical Composition ◽

Longitudinal Direction ◽

Ring Rolling ◽

Design Strategies ◽

Noticeable Effect ◽

Heavy Section ◽

Microstructure And Mechanical Properties ◽

Impact Energies ◽

The Impact

Uniformity of microstructure and mechanical properties is required for the heavy section steel. In the present work, a heavy section wind tower flange was manufactured by controlled ring-rolling. Post-rolling heat treatment was employed to optimize the microstructure and mechanical properties. The chemical composition, microstructure and mechanical properties in different zones of the flange were investigated. The results showed that the chemical composition and microstructure were uniformly distributed in the flange. The tensile strength showed similar values in different sampling locations. The strain and impact energies of specimens prepared along the longitudinal direction were higher than that prepared along both the radius and thickness directions. Notch direction did not have noticeable effect on the impact energy. It is demonstrated that the designed process is effective for producing heavy section steel with improved quality.

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Shared Bacterial and Viral Respiratory Agents in Bighorn Sheep (Ovis canadensis), Domestic Sheep (Ovis aries), and Goats (Capra hircus) in Montana

Veterinary Medicine International ◽

10.4061/2011/162520 ◽

2011 ◽

Vol 2011 ◽

pp. 1-12 ◽

Cited By ~ 4

Author(s):

David S. Miller ◽

Glen C. Weiser ◽

Keith Aune ◽

Brent Roeder ◽

Mark Atkinson ◽

...

Keyword(s):

Disease Outbreaks ◽

Bighorn Sheep ◽

Cross Sectional Study ◽

Ovis Canadensis ◽

Ovis Aries ◽

Capra Hircus ◽

Domestic Sheep ◽

Infectious Agents ◽

Cross Sectional ◽

The Impact

Transmission of infectious agents from livestock reservoirs has been hypothesized to cause respiratory disease outbreaks in bighorn sheep (Ovis canadensis), and land management policies intended to limit this transmission have proven controversial. This cross-sectional study compares the infectious agents present in multiple populations of bighorn sheep near to and distant from their interface with domestic sheep (O. aries) and domestic goat (Capra hircus) and provides critical baseline information needed for interpretations of cross-species transmission risks. Bighorn sheep and livestock shared exposure to Pasteurellaceae, viral, and endoparasite agents. In contrast, although the impact is uncertain,Mycoplasmasp. was isolated from livestock but not bighorn sheep. These results may be the result of historic cross-species transmission of agents that has resulted in a mosaic of endemic and exotic agents. Future work using longitudinal and multiple population comparisons is needed to rigorously establish the risk of outbreaks from cross-species transmission of infectious agents.

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Microstructure and Mechanical Properties of Heat-Affected Zone of Repeated Welding AISI 304N Austenitic Stainless Steel by Gleeble Simulator

Metals ◽

10.3390/met8100773 ◽

2018 ◽

Vol 8 (10) ◽

pp. 773

Author(s):

Y.H. Guo ◽

Li Lin ◽

Donghui Zhang ◽

Lili Liu ◽

M.K. Lei

Keyword(s):

Mechanical Properties ◽

Stainless Steel ◽

Austenitic Stainless Steel ◽

Impact Energy ◽

Heat Affected Zone ◽

Ferrite Content ◽

Equipment Safety ◽

Microstructure And Mechanical Properties ◽

Δ Ferrite ◽

The Impact

Heat-affected zone (HAZ) of welding joints critical to the equipment safety service are commonly repeatedly welded in industries. Thus, the effects of repeated welding up to six times on the microstructure and mechanical properties of HAZ for AISI 304N austenitic stainless steel specimens were investigated by a Gleeble simulator. The temperature field of HAZ was measured by in situ thermocouples. The as-welded and one to five times repeated welding were assigned as-welded (AW) and repeated welding 1–5 times (RW1–RW5), respectively. The austenitic matrices with the δ-ferrite were observed in all specimens by the metallography. The δ-ferrite content was also determined using magnetic and metallography methods. The δ-ferrite had a lathy structure with a content of 0.69–3.13 vol.%. The austenitic grains were equiaxial with an average size of 41.4–47.3 μm. The ultimate tensile strength (UTS) and yield strength (YS) mainly depended on the δ-ferrite content; otherwise, the impact energy mainly depended on both the austenitic grain size and the δ-ferrite content. The UTS of the RW1–RW3 specimens was above 550 MPa following the American Society of Mechanical Engineers (ASME) standard. The impact energy of all specimens was higher than that in ASME standard at about 56 J. The repeated welding up to three times could still meet the requirements for strength and toughness of welding specifications.

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The Effect of Aging Heat Treatment on the Microstructure and Mechanical Properties of 10Cr20Ni25Mo1.5NbN Austenitic Steel

High Temperature Materials and Processes ◽

10.1515/htmp-2014-0155 ◽

2016 ◽

Vol 35 (1) ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

Zhiyuan Liang ◽

Wanhua Sha ◽

Qinxin Zhao ◽

Chongbin Wang ◽

Jianyong Wang ◽

...

Keyword(s):

Electron Microscopy ◽

Mechanical Properties ◽

Heat Treatment ◽

Austenitic Steel ◽

Treatment Time ◽

Aging Treatment ◽

Secondary Phases ◽

Aging Heat Treatment ◽

Microstructure And Mechanical Properties ◽

The Impact

AbstractThe effect of aging heat treatment on the microstructure and mechanical properties of 10Cr20Ni25Mo1.5NbN austenitic steel was investigated in this article. The microstructure was characterized by scanning electron microscopy, energy dispersive spectrometry and transmission electron microscopy. Results show that the microstructure of 10Cr20Ni25Mo1.5NbN austenitic is composed of austenite. This steel was strengthened by precipitates of secondary phases that were mainly M23C6 carbides and NbCrN nitrides. As aging treatment time increased, the tensile strength first rose (0–3,000 h) and then fell (3,000–5,000 h) due to the decrease of high density of dislocations. The impact absorbed energy decreased sharply, causing the sulfides to precipitate at the grain boundary. Therefore, the content of sulfur should be strictly controlled in the steelmaking process.

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Microstructure and Mechanical Properties of 14Cr-ODS Steels with Zr Addition

High Temperature Materials and Processes ◽

10.1515/htmp-2018-0067 ◽

2019 ◽

Vol 38 (2019) ◽

pp. 404-410 ◽

Cited By ~ 4

Author(s):

Weijuan Li ◽

Haijian Xu ◽

Xiaochun Sha ◽

Jingsong Meng ◽

Zhaodong Wang

Keyword(s):

Mechanical Properties ◽

Hot Isostatic Pressing ◽

Oxide Dispersion Strengthened ◽

Nominal Composition ◽

Ods Steel ◽

Zr Addition ◽

Microstructure And Mechanical Properties ◽

The Matrix ◽

Ods Steels ◽

The Impact

AbstractIn this study, oxide dispersion strengthened (ODS) ferritic steels with nominal composition of Fe–14Cr–2W–0.35Y2O3 (14Cr non Zr-ODS) and Fe–14Cr–2W–0.3Zr–0.35Y2O3 (14Cr–Zr-ODS) were fabricated by mechanical alloying (MA) and hot isostatic pressing (HIP) technique to explore the impact of Zr addition on the microstructure and mechanical properties of 14Cr-ODS steels. Microstructure characterization revealed that Zr addition led to the formation of finer oxides, which was identified as Y4Zr3O12, with denser dispersion in the matrix. The ultimate tensile strength (UTS) of the non Zr-ODS steel is about 1201 MPa, but UTS of the Zr-ODS steel increases to1372 MPa, indicating the enhancement of mechanical properties by Zr addition.

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Influence of Vanadium on the Microstructure and Mechanical Properties of Medium-Carbon Steels for Wheels

Metals ◽

10.3390/met8120978 ◽

2018 ◽

Vol 8 (12) ◽

pp. 978 ◽

Cited By ~ 4

Author(s):

Pengfei Wang ◽

Zhaodong Li ◽

Guobiao Lin ◽

Shitong Zhou ◽

Caifu Yang ◽

...

Keyword(s):

Mechanical Properties ◽

Impact Toughness ◽

Grain Refinement ◽

Carbon Steels ◽

Precipitation Strengthening ◽

Austenite Grain Size ◽

Medium Carbon ◽

Microstructure And Mechanical Properties ◽

Medium Carbon Steels ◽

The Impact

Steels used for high-speed train wheels require a combination of high strength, toughness, and wear resistance. In 0.54% C-0.9% Si wheel steel, the addition of 0.075 or 0.12 wt % V can refine grains and increase the ferrite content and toughness, although the influence on the microstructure and toughness is complex and poorly understood. We investigated the effect of 0.03, 0.12, and 0.23 wt % V on the microstructure and mechanical properties of medium-carbon steels (0.54% C-0.9% Si) for train wheels. As the V content increased, the precipitation strengthening increased, whereas the grain refinement initially increased, and then it remained unchanged. The increase in strength and hardness was mainly due to V(C,N) precipitation strengthening. Increasing the V content to 0.12 wt % refined the austenite grain size and pearlite block size, and increased the density of high-angle ferrite boundaries and ferrite volume fraction. The grain refinement improved the impact toughness. However, the impact toughness then reduced as the V content was increased to 0.23 wt %, because grain refinement did not further increase, whereas precipitation strengthening and ferrite hardening occurred.

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Differences in leukocyte differentiation molecule abundances on domestic sheep (Ovis aries) and bighorn sheep (Ovis canadensis) neutrophils identified by flow cytometry

Comparative Immunology Microbiology and Infectious Diseases ◽

10.1016/j.cimid.2016.04.006 ◽

2016 ◽

Vol 46 ◽

pp. 40-46 ◽

Cited By ~ 7

Author(s):

Margaret A. Highland ◽

David A. Schneider ◽

Stephen N. White ◽

Sally A. Madsen-Bouterse ◽

Donald P. Knowles ◽

...

Keyword(s):

Flow Cytometry ◽

Bighorn Sheep ◽

Ovis Canadensis ◽

Ovis Aries ◽

Domestic Sheep

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Effect of Tempering Time on Microstructure and Mechanical Properties of SA738 Gr.B Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.1016.1739 ◽

2021 ◽

Vol 1016 ◽

pp. 1739-1746

Author(s):

Yan Mei Li ◽

Shu Zhan Zhang ◽

Zai Wei Jiang ◽

Sheng Yu ◽

Qi Bin Ye ◽

...

Keyword(s):

Mechanical Properties ◽

Impact Toughness ◽

Yield Strength ◽

Microstructure Evolution ◽

Impact Energy ◽

Nuclear Power ◽

Microstructure And Mechanical Properties ◽

The Impact ◽

Tempering Time

The effect of tempering time on the microstructure and mechanical properties of SA738 Gr.B nuclear power steel was studied using SEM, TEM and thermodynamic software, and its precipitation and microstructure evolution during tempering were clarified. The results showed that SA738 Gr.B nuclear power steel has better comprehensive mechanical properties after tempering at 650 °C for 1h. With the extension of the tempering time, M3C transformed into M23C6 with increasing size, which affected the yield strength and impact energy. When the tempering time is 8h ~ 10h, due to the transformation of M3C to M23C6, the composition of matrix around the carbide changed, causing the temperature of Ac1 dropped, forming twin-martensite which deteriorated the impact toughness of the steel.

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Influence of Prior Martensite on Bainite Transformation, Microstructures, and Mechanical Properties in Ultra-Fine Bainitic Steel

Materials ◽

10.3390/ma12030527 ◽

2019 ◽

Vol 12 (3) ◽

pp. 527 ◽

Cited By ~ 10

Author(s):

Hui Guo ◽

Xianying Feng ◽

Aimin Zhao ◽

Qiang Li ◽

Jun Ma

Keyword(s):

Mechanical Properties ◽

Retained Austenite ◽

Bainitic Ferrite ◽

Growth Direction ◽

Bainitic Transformation ◽

Bainitic Steel ◽

Bainite Transformation ◽

Multiphase Microstructure ◽

Microstructures And Mechanical Properties ◽

The Impact

A multiphase microstructure comprising of different volume fractions of prior martensite and ultra-fine bainite (bainitic ferrite and retained austenite) was obtained by quenching to certain temperatures, followed by isothermal bainitic transformation. The effect of the prior martensite transformation on the bainitic transformation behavior, microstructures, and mechanical properties were discussed. The results showed that the prior martensite accelerated the subsequent low-temperature bainite transformation, and the incubation period and completion time of the bainite reaction were significantly shortened. This phenomenon was attributed to the enhanced nucleation ratio caused by the introduced strain in austenite, due to the formation of prior martensite and a carbon partitioning between the prior martensite and retained austenite. Moreover, the prior martensite could influence the crystal growth direction of bainite ferrite, refine bainitic ferrite plates, and reduce the dimension of blocky retained austenite, all of which were responsible for improving the mechanical properties of the ultra-fine bainitic steel. When the content of the prior martensite reached 15%, the investigated steels had the best performance, which were 1800 MPa and 21% for the tensile strength and elongation, respectively. Unfortunately, the increased content of the prior martensite could lead to a worsening of the impact toughness.

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