Does Thermal Annealing Affect the Mechanical Properties of Silkworm (Bombyx mori) Cocoon Silk?

2012 ◽  
Vol 1465 ◽  
Author(s):  
Emily J. Reed ◽  
Christopher Viney
Keyword(s):  
Mechanical Properties ◽  
Bombyx Mori ◽  
Microwave Radiation ◽  
Constant Strain Rate ◽  
Annealing Treatment ◽  
Tensile Tests ◽  
Conventional Heating ◽  
Heating Rates ◽  
Microwave Exposure ◽  
Property Changes

ABSTRACTIt has been reported [1] that microwave radiation can enhance many of the mechanical properties of Bombyx mori silkworm cocoon silk, as measured in constant strain rate tensile tests to failure and in stress relaxation tests. The consequences of microwave radiation will affect decisions about the use of silk in settings subjected to significant microwave exposure – for example, as a reinforcing fiber in an epoxy matrix composite that may be microwave cured, or as a component in aircraft radomes.There are two possible mechanisms by which microwave radiation may affect a material [2]: (i) the radiation may enable chemical and/or microstructural changes – and therefore property changes – in the same way that conventional heating would, or (ii) the high heating rates that are achievable by microwaving may selectively favor changes that would be masked under conventional conditions, where heating rates are low enough to give preference to changes that have a lower activation energy. Here we explore the former possibility for silk.We characterized several mechanical properties of degummed and subsequently annealed B. mori silk, and compared them to the corresponding properties of degummed B. mori silk that was not annealed. The annealing treatment was carried out at 140 °C for 7 hours (conditions that optimally increased crystal size in an unrelated study of B. mori silk [3]), and then the fibers were allowed to cool gradually to room temperature over the course of an hour. Comparison of mechanical properties revealed no differences between the materials that we tested. Thus, for annealed silk, we do not observe the enhancements that can be achieved by microwaving. We conclude that in cases where microwaving affects the properties of silk, those changes are not a simple consequence of annealing by the microwaves.

Influence of Continuous Annealing Conditions on the Microstructure and Mechanical Properties of a C-Mn Dual Phase Steel

2010 ◽  
Vol 638-642 ◽  
pp. 3479-3484 ◽  
Author(s):  
Roberta O. Rocha ◽  
Tulio M.F. Melo ◽  
Dagoberto Brandao Santos
Keyword(s):  
Mechanical Properties ◽  
Microstructural Analysis ◽  
Tensile Tests ◽  
Recrystallization Temperature ◽  
Continuous Annealing ◽  
Dual Phase ◽  
Heating Rates ◽  
Microstructure And Mechanical Properties ◽  
Annealing Cycle ◽  
Soaking Temperature

The influence of continuous annealing variables on the microstructure and mechanical properties of a C-Mn Dual Phase (DP) steel was studied. The annealing cycles were simulated using a Gleeble machine. Some specimens were quenched at different stages of the annealing cycle in order to evaluate the microstructural evolution during the annealing process. Tensile tests and microstrutural analysis were carried out. The results showed that high heating rates increased the final recrystallization temperature and as a consequence the microstructure obtained was refined. Austenite grain nucleation and growth were also influenced by the heating rates. Soaking temperature was the most influent variable on the mechanical properties, i. e., the yield strength increased and the tensile strength decreased with an increase in the soaking temperature. Microstructural analysis showed that not only martensite, but also bainite and martensite-retained autenite constituent (MA) were formed. Undissolved carbides were also detected by transmission electron microscopy.

scholarly journals Feasibility study of a novel hot stamping process for Ti6Al4V alloy

2018 ◽  
Vol 190 ◽  
pp. 08001
Author(s):  
Mateusz Kopec ◽  
Kehuan Wang ◽  
Yaoqi Wang ◽  
Liliang Wang ◽  
Jianguo Lin
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Phase Transformation ◽  
New Technology ◽  
Hot Stamping ◽  
Constant Strain Rate ◽  
Tensile Tests ◽  
Ti6al4v Titanium Alloy ◽  
Stamping Process ◽  
Forming Tools

To investigate the feasibility of a novel hot stamping process for the Ti6Al4V titanium alloy using low temperature forming tools, mechanical properties of the material were studied using hot tensile tests at a temperature range of 600 - 900°C with a constant strain rate of 1s-1. Hot stamping tests were carried out to verify the feasibility of this technology and identify the forming window for the material. Results show that when the deformation temperature was lower than 700°C, the amount of elongation was less than 20%, and it also had little change with the temperature. However, when the temperature was higher than 700°C, a good ductility of the material can be achieved. During the forming tests, parts failed at lower temperatures (600°C) due to the limited formability and also failed at higher temperatures (950°C) due to the phase transformation. The post-form hardness firstly decreased with the temperature increasing due to recovery and then increased due to the phase transformation. Qualified parts were formed successfully between temperatures of 750 - 850°C, which indicates that this new technology has a great potential in forming titanium alloys sheet components.

Influence of Annealing Treatment on Formability and Springback for Magnesium Alloy Sheets

2010 ◽  
Vol 443 ◽  
pp. 189-194 ◽  
Author(s):  
Dae Yong Kim ◽  
Bum Kyu Hwang ◽  
Young Seon Lee ◽  
Sang Woo Kim ◽  
Young Hoon Moon
Keyword(s):  
Mechanical Properties ◽  
Magnesium Alloy ◽  
Room Temperature ◽  
Annealing Treatment ◽  
Tensile Tests ◽  
Strip Casting ◽  
Bending Tests ◽  
Magnesium Alloy Az31 ◽  
Twin Roll ◽  
Springback Angle

The purpose of this work is to experimentally investigate the effect of annealing treatment on the formability and springback at room temperature for magnesium alloy AZ31 sheets, which were produced by rolling through reversible warm mill after twin roll strip casting. Microstructure evolutions were investigated using OM after annealing at temperature raging from 350°C to 450°C. Tensile tests at room temperature were performed to show the influence of annealing treatment on mechanical properties. In order to evaluate the formability in stamping processes, the Erichsen cupping tests were carried out and the Erichsen number were measured. As for springback, the V shaped air bending tests were achieved and the angle changes after springback were collected. The experimental results showed that Erichsen numbers increased by the annealing treatment, while springback angle decreased.

Mechanical properties of Bombyx mori silkworm silk subjected to microwave radiation

2014 ◽  
Vol 29 (7) ◽  
pp. 833-842 ◽  
Author(s):  
Emily J. Reed ◽  
Christopher Viney
Keyword(s):  
Mechanical Properties ◽  
Bombyx Mori ◽  
Microwave Radiation ◽  
Image Position ◽  
Silkworm Silk

Abstract

Microstructure and Mechanical Properties of a Novel Ti-6.5Al-2Sn-4Zr-1.5Mo-2Nb-0.25Fe-0.2Si High-Temperature Titanium Alloy

2020 ◽  
Vol 993 ◽  
pp. 351-357
Author(s):  
Ming Yu Zhao ◽  
Xiao Yun Song ◽  
Wen Jing Zhang ◽  
Yu Wei Diao ◽  
Wen Jun Ye ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Room Temperature ◽  
Annealing Treatment ◽  
Tensile Tests ◽  
Electron Backscattered Diffraction ◽  
Two Phase ◽  
Bimodal Structure ◽  
Α Phase ◽  
Microstructure And Mechanical Properties

The Ti-6.5Al-2Sn-4Zr-1.5Mo-2Nb-0.25Fe-0.2Si (wt%) alloy is a novel two-phase high temperature alloy for short-term application. The effects of different heat treatments on the microstructure and mechanical properties were investigated through electron probe microanalysis (EPMA), optical microcopy (OM), scanning electron microscope (SEM), electron backscattered diffraction (EBSD) and tensile tests at room temperature and 650°C. Subjected to the annealing treatment at α+β region (1010 °C/2 h, FC to 990 °C+990 °C/2 h, AC), the microstructure was composed of bimodal structure, which consists of equiaxed primary α (αp) phase and lamellar transformed β (βt) structure. As a strong β stabilizer, the content of Fe in α phase is much less than that in β phase. Annealing at β region (1040 °C/2 h, AC) resulted in the formation of widmannstatten structure, consisting of coarse raw β grain and secondary α phase precipitated on the β grain. With respect to the tensile property, different heat-treated alloys obtained similar strength. However, widmannstatten structure was characterized by lower plasticity, with the elongation only half that of bimodal structure. The fracture characteristics at room temperature for the alloy with bimodal structure and widmannstatten structure are dominated by ductile fracture and cleavage fracture, respectively.

scholarly journals Effects of Double-Stage Annealing Parameters on Tensile Mechanical Properties of Initial Aging Deformed GH4169 Superalloy

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4339
Author(s):  
Guanqiang Wang ◽  
Mingsong Chen ◽  
Yongcheng Lin ◽  
Yumin Lou ◽  
Hongbin Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Fracture Mode ◽  
Room Temperature ◽  
Shear Fracture ◽  
Annealing Treatment ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Water Cooling ◽  
Gh4169 Superalloy

This study takes large size samples after hot-upsetting as research objects and aims to investigate the optimization double-stage annealing parameters for improving the mechanical properties of hot-upsetting samples. The double-stage annealing treatments and uniaxial tensile tests for hot-upsetting GH4169 superalloy were finished firstly. Then, the fracture mode was also studied. The results show that the strength of hot-upsetting GH4169 superalloy can be improved by the double-stage annealing treatment, but the effect of annealing parameters on the elongation of GH4169 alloy at high temperature and room temperature is not significant. The fracture mode of annealed samples at high-temperature and room-temperature tensile tests is a mixture of shear fracture and quasi-cleavage fracture while that of hot-upsetting sample is a shear fracture. The macroscopic expressions for the two fracture modes belong to ductile fracture. Moreover, it is also found that the improvement of strength by the double-stage annealing treatment is greater than the single-stage annealing treatment. This is because the homogeneity of grains plays an important role in the improvement of strength for GH4169 superalloy when the average grain size is similar. Based on a comprehensive consideration, the optimal annealing route is determined as 900 °C × 9–12 h(water cooling) + 980 °C × 60 min(water cooling).

scholarly journals The Effect of Initial Annealing Microstructures on the Forming Characteristics of Ti–4Al–2V Titanium Alloy

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 576 ◽  
Author(s):  
Bin Yan ◽  
Hongbo Li ◽  
Jie Zhang ◽  
Ning Kong
Keyword(s):  
Mechanical Properties ◽  
Titanium Alloy ◽  
Room Temperature ◽  
Constant Strain Rate ◽  
Annealing Treatment ◽  
Fracture Morphology ◽  
Sem Analysis ◽  
Α Phase ◽  
Plastic Forming ◽  
Forming Characteristics

In this study, the effect of initial annealing microstructure of Ti–4Al–2V (TA17) alloy on forming characteristic was studied, so as to provide a basis for quality control of plastic forming of titanium alloy parts. The titanium alloy always undergoes annealing treatment before forming, due to different microstructures present different mechanical properties. The TA17 with different microstructures are obtained by means of various annealing treatment temperatures. The tensile behavior of TA17 is investigated at room temperature and 900 °C under constant strain rate of 0.01 s−1. The experimental results show that the mechanical properties of TA17 are sensitive to the initial microstructure before deformation. The microstructure of TA17 at 850 °C (2 h) is the equiaxed primary α-phase after the annealing process. It exhibits good plasticity at room temperature. This phenomenon is also confirmed from fracture morphology from the scanning electron microscope (SEM) analysis. At 900 °C, which is a high tensile temperature, the alloy with equiaxed primary α-phase performs outstanding plasticity compared with other microstructures. This work establishes a good understanding on the relationship between the mechanical properties and microstructures of TA17 at a wide temperature range.

Influence of Duplex Annealing on the Microstructure and Mechanical Properties of Ti62421S Titanium Alloy Plate

2015 ◽  
Vol 816 ◽  
pp. 804-809 ◽  
Author(s):  
Xiao Yun Song ◽  
Yong Ling Wang ◽  
Wen Jing Zhang ◽  
Song Xiao Hui ◽  
Wen Jun Ye
Keyword(s):  
Mechanical Properties ◽  
Room Temperature ◽  
Volume Fraction ◽  
Annealing Treatment ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Alloy Plate ◽  
Β Phase ◽  
Α Phase ◽  
Microstructure And Mechanical Properties

The effects of different duplex annealing treatments on the microstructure and mechanical properties of Ti62421S alloy plate were studied by optical microscope (OM), scanning electron microscope (SEM), electron probe microanalysis (EPMA) and tensile tests, The experimental results indicated that the original microstructure of Ti62421S was composed of primary α phase (αp) and intergranular β phase. With the increase of first-stage annealing temperature, the volume fraction of equiaxed αp phase decreased. In contrast, the content of transformed β structure (βt) increased, and the width of lamellar secondary α phase (αs) in βt increased. Consequently, the yield strength (σ0.2) and ultimate tensile strength (σb) at room temperature and 600°C increased, while the elongation (δ5) declined. After 1000°C/2h/AC+ 600°C/2h/AC duplex annealing treatment, Ti62421S alloy plate showed superior tensile properties. The values of σb and δ5 at room temperature reached 1133MPa and 6%, as well as the value of σb at 600°C exceeded 710MPa.

Microstructure and Mechanical Properties of Ti62421S High Temperature Titanium Alloy with Different Heat Treatments

2017 ◽  
Vol 898 ◽  
pp. 574-578
Author(s):  
Xiao Yun Song ◽  
Yong Ling Wang ◽  
Wen Jing Zhang ◽  
Wen Jun Ye ◽  
Song Xiao Hui
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Annealing Temperature ◽  
Elevated Temperatures ◽  
Annealing Treatment ◽  
Tensile Tests ◽  
Alloy Plate ◽  
Microstructure And Mechanical Properties ◽  
Transmission Electron ◽  
Different Temperatures

In this paper, three different double annealing treatments were applied on the 3mm-thick Ti-6Al-2Sn-4Zr-1Mo-2Nb-0.2Si (Ti62421S) alloy plate. Optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and tensile tests were used to investigate the microstructure and mechanical properties under different temperatures of Ti62421S alloy. The results show that the content of primary α phase (αp) decreases while transformed β structure (βt) increases with the increasing first-stage annealing temperature. After double annealing treatment, ordered α2 phase particles precipitate within αp and the size increases with first annealing temperature. This leads to that with increasing first annealing temperature, ultimate tensile strength (UTS) at 600~650°C increases while elongation decreases. After 1000°C/1h/AC+ 750°C/2h/AC annealing, Ti62421S alloy plate exhibits superior combination of mechanical properties at room and elevated temperatures.

scholarly journals Effect of Compositional and Processing Variations in New 5182-Type AlMgMn Alloys on Mechanical Properties and Deformation Surface Quality

Materials ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1645 ◽  
Author(s):  
Paul Ebenberger ◽  
Peter J. Uggowitzer ◽  
Bodo Gerold ◽  
Stefan Pogatscher
Keyword(s):  
Mechanical Properties ◽  
Cold Rolling ◽  
Surface Quality ◽  
Surface Characterization ◽  
Annealing Treatment ◽  
Tensile Tests ◽  
Salt Bath ◽  
Processing Route ◽  
Treatment Procedures ◽  
Deformation Surface

Laboratory-scale sheets of 5182-type AlMgMn alloys with varying Mg and Mn contents and additions of different amounts of Zn, Cu, Zr and Er were studied. The sheets were produced using two different cold-rolling degrees and two soft-annealing treatment procedures: air-circulated furnace annealing at 370 °C with subsequent furnace cooling, and salt-bath annealing with subsequent water quenching. Mechanical properties and deformation surface quality were studied via tensile tests with simultaneous visual surface characterization. The influence of the chemical composition and the processing route on grain size, mechanical properties, and surface quality is discussed in the study. A reduction in the Mg content improves the surface quality after plastic deformation, but at the expense of the mechanical properties. The results suggest the presence of an optimum Mn content in terms of optical appearance and mechanical properties. Adding Zr largely inhibits recrystallization, which is reflected in a textured microstructure. Adding Er affects neither the surface quality nor the mechanical properties. Specific combinations of Zn or Cu addition, cold-rolling degree, and heat treatment generate significant improvements in the mechanical and optical properties. In general, annealing at high temperature with subsequent quenching leads to enhanced surface quality and mechanical properties, and adding Zn enables further noteworthy improvements.

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