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A low-cost hierarchical nanostructured beta-titanium alloy with high strength.

Devaraj A, Joshi VV, Srivastava A, Manandhar S, Moxson V, Duz VA, Lavender C - Nat Commun (2016)

Bottom Line: Lightweighting of automobiles by use of novel low-cost, high strength-to-weight ratio structural materials can reduce the consumption of fossil fuels and in turn CO2 emission.Our results suggest that the high number density of nanoscale α-phase precipitates in the β-phase matrix is due to ω assisted nucleation of α resulting in high tensile strength, greater than any current commercial titanium alloy.Thus hierarchical nanostructured Ti185 serves as an excellent candidate for replacing costlier titanium alloys and other structural alloys for cost-effective lightweighting applications.

View Article: PubMed Central - PubMed

Affiliation: Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, USA.

ABSTRACT
Lightweighting of automobiles by use of novel low-cost, high strength-to-weight ratio structural materials can reduce the consumption of fossil fuels and in turn CO2 emission. Working towards this goal we achieved high strength in a low cost β-titanium alloy, Ti-1Al-8V-5Fe (Ti185), by hierarchical nanostructure consisting of homogenous distribution of micron-scale and nanoscale α-phase precipitates within the β-phase matrix. The sequence of phase transformation leading to this hierarchical nanostructure is explored using electron microscopy and atom probe tomography. Our results suggest that the high number density of nanoscale α-phase precipitates in the β-phase matrix is due to ω assisted nucleation of α resulting in high tensile strength, greater than any current commercial titanium alloy. Thus hierarchical nanostructured Ti185 serves as an excellent candidate for replacing costlier titanium alloys and other structural alloys for cost-effective lightweighting applications.

No MeSH data available.


Related in: MedlinePlus

TEM analysis of STA conditions.Bright-field TEM images showing (a) grain boundary α and intragranular α and (b) primary and secondary intragranular α in a STA 1,300-900-2 specimen. Scale bars are 200 nm in both (a–c) grain boundary α and nanoscale secondary intragranular α (scale bar is 200 nm) and (d) high-density nanoscale secondary intragranular α (scale bar is 100 nm) in a STA 1,450-900-2 specimen.
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f3: TEM analysis of STA conditions.Bright-field TEM images showing (a) grain boundary α and intragranular α and (b) primary and secondary intragranular α in a STA 1,300-900-2 specimen. Scale bars are 200 nm in both (a–c) grain boundary α and nanoscale secondary intragranular α (scale bar is 200 nm) and (d) high-density nanoscale secondary intragranular α (scale bar is 100 nm) in a STA 1,450-900-2 specimen.

Mentions: The decrease in the number density as well as increase in the inter-particle spacing should lead to decrease in the strength17, which is in contradiction to the trend observed for tensile strength in Fig. 1b. Hence we carried out transmission electron microscopy (TEM) analysis of the microstructure of the specimens to check the presence of any smaller (nanometer) size scale precipitates. The bright field TEM images of STA condition 1,300-900-2 are shown in Fig. 3a,b, whereas the same for STA condition 1,450-900-2 are shown in Fig. 3c,d. The bright-field TEM images of STA 1,300-900-2 specimen show the presence of grain boundary α, primary intragranular α and additionally some fine scale α precipitates of an average width of 54 nm and length of 386 nm with an inter-particle spacing of roughly 80 nm. This fine scale α precipitate will be referred to as secondary α precipitate in the remainder of this paper. The secondary α precipitates seen in the TEM bright-field images of STA 1,450-900-2 (Fig. 3c,d) are clearly much smaller (34 nm wide and 66 nm long) and with an inter-particle spacing less than 45 nm, and hence much more densely distributed than the secondary α in STA 1,300-900-2.


A low-cost hierarchical nanostructured beta-titanium alloy with high strength.

Devaraj A, Joshi VV, Srivastava A, Manandhar S, Moxson V, Duz VA, Lavender C - Nat Commun (2016)

TEM analysis of STA conditions.Bright-field TEM images showing (a) grain boundary α and intragranular α and (b) primary and secondary intragranular α in a STA 1,300-900-2 specimen. Scale bars are 200 nm in both (a–c) grain boundary α and nanoscale secondary intragranular α (scale bar is 200 nm) and (d) high-density nanoscale secondary intragranular α (scale bar is 100 nm) in a STA 1,450-900-2 specimen.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4821990&req=5

f3: TEM analysis of STA conditions.Bright-field TEM images showing (a) grain boundary α and intragranular α and (b) primary and secondary intragranular α in a STA 1,300-900-2 specimen. Scale bars are 200 nm in both (a–c) grain boundary α and nanoscale secondary intragranular α (scale bar is 200 nm) and (d) high-density nanoscale secondary intragranular α (scale bar is 100 nm) in a STA 1,450-900-2 specimen.
Mentions: The decrease in the number density as well as increase in the inter-particle spacing should lead to decrease in the strength17, which is in contradiction to the trend observed for tensile strength in Fig. 1b. Hence we carried out transmission electron microscopy (TEM) analysis of the microstructure of the specimens to check the presence of any smaller (nanometer) size scale precipitates. The bright field TEM images of STA condition 1,300-900-2 are shown in Fig. 3a,b, whereas the same for STA condition 1,450-900-2 are shown in Fig. 3c,d. The bright-field TEM images of STA 1,300-900-2 specimen show the presence of grain boundary α, primary intragranular α and additionally some fine scale α precipitates of an average width of 54 nm and length of 386 nm with an inter-particle spacing of roughly 80 nm. This fine scale α precipitate will be referred to as secondary α precipitate in the remainder of this paper. The secondary α precipitates seen in the TEM bright-field images of STA 1,450-900-2 (Fig. 3c,d) are clearly much smaller (34 nm wide and 66 nm long) and with an inter-particle spacing less than 45 nm, and hence much more densely distributed than the secondary α in STA 1,300-900-2.

Bottom Line: Lightweighting of automobiles by use of novel low-cost, high strength-to-weight ratio structural materials can reduce the consumption of fossil fuels and in turn CO2 emission.Our results suggest that the high number density of nanoscale α-phase precipitates in the β-phase matrix is due to ω assisted nucleation of α resulting in high tensile strength, greater than any current commercial titanium alloy.Thus hierarchical nanostructured Ti185 serves as an excellent candidate for replacing costlier titanium alloys and other structural alloys for cost-effective lightweighting applications.

View Article: PubMed Central - PubMed

Affiliation: Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99354, USA.

ABSTRACT
Lightweighting of automobiles by use of novel low-cost, high strength-to-weight ratio structural materials can reduce the consumption of fossil fuels and in turn CO2 emission. Working towards this goal we achieved high strength in a low cost β-titanium alloy, Ti-1Al-8V-5Fe (Ti185), by hierarchical nanostructure consisting of homogenous distribution of micron-scale and nanoscale α-phase precipitates within the β-phase matrix. The sequence of phase transformation leading to this hierarchical nanostructure is explored using electron microscopy and atom probe tomography. Our results suggest that the high number density of nanoscale α-phase precipitates in the β-phase matrix is due to ω assisted nucleation of α resulting in high tensile strength, greater than any current commercial titanium alloy. Thus hierarchical nanostructured Ti185 serves as an excellent candidate for replacing costlier titanium alloys and other structural alloys for cost-effective lightweighting applications.

No MeSH data available.


Related in: MedlinePlus