Deformation Behavior of Fe-Al Single Crystals Containing Fe2AlTi Precipitates

Fe-20Al-5Ti (at.%) single crystals composed of the bcc Fe-Al matrix and the Fe2AlTi precipitates with the L21 structure was examined. In the single crystals furnace-cooled (FC) from 1373 K to room temperature, coarse Fe2AlTi phase about 300 nm in diameter were precipitated in the bcc matrix. A misfit strain and a dissolution temperature of the L21 precipitates are +0.59% and 1151 K, respectively. The single crystals exhibited high yield stress above 600 MPa up to 973 K while further increase in temperature resulted in a decrease in yield stress due to the dissolution of the precipitates. In the FC crystals, 1/2<111> dislocations in the bcc matrix bypassed the coarse L21 precipitates due to their large misfit strain, resulting in high strength. In contrast, the fine L21 precipitates about 30 nm in diameter were observed in the crystals after solutionization and annealing at 873 K. The crystals with the fine L21 precipitates demonstrated high yield stress above 1100 MPa at and below 773 K. Uncoupled or paired 1/2<111> dislocations cut the fine L21 precipitates, leaving an anti-phase boundary (APB) inside the precipitates. The APB inside the precipitates was considered to be responsible for strong precipitation hardening.

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Deformation Behavior of Fe-Al-Co-Ti Single Crystals Containing Co2AlTi Precipitates

Materials Science Forum ◽

10.4028/www.scientific.net/msf.879.2210 ◽

2016 ◽

Vol 879 ◽

pp. 2210-2215 ◽

Cited By ~ 1

Author(s):

Hiroyuki Y. Yasuda ◽

Ryota Kobayashi

Keyword(s):

Single Crystals ◽

Yield Stress ◽

Deformation Behavior ◽

Room Temperature ◽

High Strength ◽

Misfit Strain ◽

High Yield ◽

Precipitate Size ◽

High Yield Stress

Deformation behavior of Fe-15Al-18Co-3Ti (at.%) single crystals containing the Co2AlTi precipitates was examined. In the single crystals furnace-cooled (FC) from 1373 K to room temperature, coarse Co2AlTi phase with the L21 structure was precipitated in the bcc matrix. The L21 phase showed a cuboidal shape with a misfit strain of 0.59%. It is also noted that large amount of Fe substituted for Co in the Co2AlTi precipitates. The FC single crystals exhibited high yield stress above 600 MPa up to 823 K while further increase in temperature resulted in a decrease in yield stress. In the FC crystals, 1/2<111> dislocations in the bcc matrix bypassed the coarse L21 precipitates due to their large misfit strain, resulting in high strength. In contrast, the fine L21 precipitates about 30 nm in diameter were observed in the crystals after solutionization and annealing at 823 K. The crystals with the fine L21 precipitates demonstrated high yield stress above 1400 MPa at room temperature. Paired 1/2<111> dislocations cut the fine L21 precipitates, which led to high strength. The dependence of the yield stress on the precipitate size was also discussed.

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Deformation Behavior of Fe-Al-Co Single Crystals Containing CoAl Precipitates

Materials Science Forum ◽

10.4028/www.scientific.net/msf.783-786.2869 ◽

2014 ◽

Vol 783-786 ◽

pp. 2869-2874 ◽

Cited By ~ 1

Author(s):

Hiroyuki Y. Yasuda ◽

Kentaro Soma ◽

Yoshiaki Odawara

Keyword(s):

Single Crystals ◽

Deformation Behavior ◽

Volume Fraction ◽

High Strength ◽

Misfit Strain ◽

High Yield ◽

The Matrix ◽

Primary Slip System ◽

The Difference ◽

B2 Structure

The effect of the CoAl precipitates on the deformation behavior of Fe-15.0Al-15.0Co (at.%) single crystals was examined. The spherical CoAl phase with the B2 structure was precipitated in the single crystals and was stable below 974 K. The bcc matrix and CoAl phase satisfied the cube-on-cube orientation relationship with a misfit strain of 0.25%. The single crystals showed a high yield stress up to 923 K while the stress dropped at 1023 K due to the dissolution of the CoAl phase into the matrix. Moreover, the activated sip system of the crystals containing the CoAl precipitates depended strongly on loading axis. At <149> orientation, {101} <111> slip favorable for the bcc matrix and the CoAl precipitates were sheared by a pair of 1/2<111> dislocations without forming Orowan loops. The CoAl single phase was known to hardly deform by <111> slip which resulted in high strength at <149> orientation. In contrast, {010} <001> or {hk0} <001> slip favorable for the CoAl precipitates was activated at <011> orientation, although the volume fraction of the CoAl phase was very small. <001> slip was generally impossible to take place in the bcc matrix, leading to the extreme hardening. Therefore, the difference in primary slip system between the bcc matrix and CoAl precipitates was responsible for the significant precipitation hardening.

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Electrorheological fluid with an extraordinarily high yield stress

Applied Physics Letters ◽

10.1063/1.1446999 ◽

2002 ◽

Vol 80 (5) ◽

pp. 888-890 ◽

Cited By ~ 42

Author(s):

Yuling Zhang ◽

Kunquan Lu ◽

Guanghui Rao ◽

Yu Tian ◽

Shaohua Zhang ◽

...

Keyword(s):

Yield Stress ◽

Electrorheological Fluid ◽

High Yield ◽

High Yield Stress

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Plastic Deformation of Mo(Si,Al)2 Single Crystals with the C40 Structure

MRS Proceedings ◽

10.1557/proc-460-605 ◽

1996 ◽

Vol 460 ◽

Author(s):

M. Moriwaki ◽

K. Ito ◽

H. Inui ◽

M. Yamaguchi

Keyword(s):

Single Crystals ◽

Deformation Behavior ◽

Basal Slip ◽

Room Temperature ◽

Slip Systems ◽

Temperature Range ◽

Al Content ◽

Partial Dislocations ◽

Increasing Temperature ◽

Critical Resolved Shear Stress

ABSTRACTThe deformation behavior of single crystals of Mo(Si,Al)2 with the C40 structure has been studied as a function of crystal orientation and Al content in the temperature range from room temperature to 1500°C in compression. Plastic flow is possible only above 1100°C for orientations where slip along <1120> on (0001) is operative and no other slip systems are observed over whole temperature range investigated. The critical resolved shear stress for basal slip decreases rapidly with increasing temperature and the Schmid law is valid. Basal slip appears to occur through a synchroshear mechanism, in which a-dislocations (b=1/3<1120>) dissociate into two synchro-partial dislocations with the identical Burgers vector(b*1/6<1120>) and each synchro-partial further dissociates into two partials on two adjacent planes.

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TIO2 BASED ELECTRORHEOLOGICAL FLUID WITH HIGH YIELD STRESS

Electrorheological Fluids and Magnetorheological Suspensions (ERMR 2004) ◽

10.1142/9789812702197_0007 ◽

2005 ◽

Author(s):

RONG SHEN ◽

XUEZHAO WANG ◽

WEIJIA WEN ◽

KUNQUAN LU

Keyword(s):

Yield Stress ◽

Electrorheological Fluid ◽

High Yield ◽

High Yield Stress

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Extensive application of TMCP steel plates to ship hulls: 40 kgf/mm2 class high yield stress steel

Marine Structures ◽

10.1016/0951-8339(88)90016-0 ◽

1988 ◽

Vol 1 (3) ◽

pp. 219-243 ◽

Cited By ~ 6

Author(s):

Susumu Machida ◽

Hiroshige Kitada ◽

Hiroshi Yajima ◽

Akinobu Kawamura

Keyword(s):

Yield Stress ◽

Steel Plates ◽

High Yield ◽

Ship Hulls ◽

High Yield Stress

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Strain Rate Dependence of the Flow Stress and Work-Hardening of Single Crystals of NI3(Al,Hf)B

MRS Proceedings ◽

10.1557/proc-364-695 ◽

1994 ◽

Vol 364 ◽

Author(s):

S. S. Ezz ◽

Y. Q. Sun ◽

P. B. Hirsch

Keyword(s):

Flow Stress ◽

Strain Rate ◽

Temperature Dependence ◽

Single Crystals ◽

Yield Stress ◽

Strain Rate Sensitivity ◽

Work Hardening ◽

Room Temperature ◽

Rate Sensitivity ◽

Controlling Mechanism

AbstractThe strain rate sensitivity ß of the flow stress τ is associated with workhardening and β=(δτ/δln ε) is proportional to the workhardening increment τh = τ - τy, where τy is the strain rate independent yield stress. The temperature dependence of β/τh reflects changes in the rate controlling mechanism. At intermediate and high temperatures, the hardening correlates with the density of [101] dislocations on (010). The nature of the local obstacles at room temperature is not established.

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