Effect of La on the crystallization behaviour of amorphous Al94−xNi6Lax (x=4–7) alloys

Sahoo, K L; Wollgarten, Markus; Haug, J.; Banhart, John

doi:10.1016/j.actamat.2005.04.034

Cited by 70 publications

(43 citation statements)

References 26 publications

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“…Literature also reports the absence of distinct T g in many metallic glass systems. [8] Sahoo et al [14] have shown by small angle neutron scattering experiments that small particles or at least fluctuations in scattering length density are present in Al-Ni-La alloys. Thus, one can argue that these glasses are not truly amorphous.…”

Section: Dsc Studymentioning

confidence: 98%

“…Zhuang et al [13] reported the eutectic crystallization of fcc-Al and metastable bcc-(AlNi) 11 La 3 -like phase in Al 89 Ni 5 La 6 alloy. Sahoo et al [14] reported that the primary crystallization pathway depends not only on the atomic radius but also on the amount of La content in Al-Ni-La amorphous alloys. A number of publications [3,12] regarding the stability and the crystallization kinetics of various Al-TM-RE amorphous alloys are available; however, information concerning the mechanical properties of the Al-TM-La with the progress of nanocrystallization and the correlation with corresponding microstructure is scanty.…”

Section: Introductionmentioning

confidence: 99%

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Mechanical Properties and Nanocrystallization Behavior of Al-Ni-La Alloys

Sahu

Chatterjee

Sahoo

2010

Metall Mater Trans A

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Rapidly solidified Al 89 Ni 6 La 5 ribbons were obtained by induction melting and ejecting the melt onto a rotating Cu wheel in an Ar atmosphere. The ribbons were investigated by differential scanning calorimetry (DSC), X-ray diffractometry (XRD), transmission electron microscopy (TEM), microindentation, and nanoindentation techniques. The XRD and TEM studies revealed that the ribbon was fully amorphous; however, DSC did not show any glass transition. The alloy undergoes two stages of crystallization. The growth of fcc-Al is responsible for the first stage, and precipitation of Al 3 Ni and Al 11 La 3 is responsible for the second stage of crystallization. Microhardness of ribbons in the as-melt-spun, partially, and fully devitrified conditions was examined and subsequently correlated with evolved microstructure. Significant improvement in hardness was observed, with the progress of primary nanocrystallization, due to the effective barrier to shear band by a hard La-rich shell around the fcc-Al nanocrystals and enrichment of the remaining amorphous matrix by the solute elements. The pile up of materials in the form of semicircular shear bands was observed around all the indentations. During nanoindentation, it was observed that hardness and modulus values were initially increased and then decreased. The reasons for such observation were also discussed.

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Section: Dsc Studymentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Mechanical Properties and Nanocrystallization Behavior of Al-Ni-La Alloys

Sahu

Chatterjee

Sahoo

2010

Metall Mater Trans A

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“…Ag or Agcontaining clusters would have a higher galvanic potential differential by virtue of the element's position in the galvanic series. The concentration fluctuations present in the Cu-and Ag-containing alloy in the as-cast condition and in all the alloys after primary crystallization are Al-rich bcc phases, the compositions of which are not very different from the composition of the remaining amorphous matrix [11]. Therefore, galvanic action between these crystals and the amorphous matrix is minimal.…”

Section: Discussionmentioning

confidence: 96%

Electrochemical response of amorphous and devitrified Al‐Ni‐La‐X (X = Ag, Cu) alloys

Roy

Mandhyan

Sahoo

et al. 2009

Materials & Corrosion

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The electrochemical response of melt-spun Al-Ni-La alloys with partial substitution of Ni after different stages of devitrification was studied. The base alloy was found to have the best corrosion resistance. It was observed that primary crystallization caused minimal deterioration in the corrosion resistance of the base alloy as compared to its amorphous state. The substitute alloys had different corrosion resistance dependent on the substituting element with the Ag containing alloy having the least resistance. This could be attributed to the operation of local galvanic cells, enhanced by chemical heterogeneities in the alloys. Secondary crystallization caused a reduction in the corrosion resistance of all the alloys due to the creation of intermetallic phases that increased the galvanic activity.

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“…It indicates that the studies of kinetics and mechanism of the second crystallization stage are very important for development of high-strength Al-based alloys for elevated temperature applications as well as for estimation of the temperature ranges of consolidation processing of rapidly quenched materials. However, until now the second crystallization stage in Al-based amorphous alloys has been not studied at the proper level (e.g., [35,36]). As in the case of amorphous phases thermal stability of nanophase composites in the present study has been characterized by the onset crystallization temperature of the second crystallization stage, T ons2 , measured at constant rate heating which has been estimated from the curves R(T)/R 0 similar to that as T ons1 (Fig.…”

Section: Activity 23 Determination Of the Parameters Of Nanocompositmentioning

confidence: 99%

Development of High Strength Thermally Stable Al-based Alloys with Nanocomposite Structure

Maslov¹

2010

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Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. REPORT DATE (DD-MM-YYYY)05-02-2010 REPORT TYPE Final Report DATES COVERED (From -To)01-Dec-06 -11-Jun-10 TITLE AND SUBTITLE PERFORMING ORGANIZATION REPORT NUMBERN/A SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES)EOARD Unit 4515 BOX 14 APO AE 09421 SPONSOR/MONITOR'S ACRONYM(S) SPONSOR/MONITOR'S REPORT NUMBER(S)STCU 06-8005 DISTRIBUTION/AVAILABILITY STATEMENTApproved for public release; distribution is unlimited. SUPPLEMENTARY NOTES ABSTRACTThis report results from a contract tasking Institute for Metal Physics, NAS of Ukraine as follows: The demands on materials set by aerospace and aircraft manufacturers include the development of alloys possessing high strength-to-weight ratios and capable to withstand high temperature exposures during service. One of the promising classes of materials which may meet these requirements are Al-based alloys with nanocomposite structures formed by partial crystallization of amorphous precursors the strength of which may exceed 1500 MPa. Solution of the problems concerning alloys chemistry and ability to tailor of certain microstructures is of prime importance for the development of new nanostructured materials. The goals of the project are to perform the systematic experimental studies of the effects of alloy composition and thermal prehistory on glassforming ability, thermal stability, crystallization behaviour and mechanical properties of a series binary, ternary and multicomponent Al-based alloys alloyed by transition metals and rare earths as well as to elaborate appropriate theoretical models of nanocrystallization processes. The main factors responsible for nanoscale microstructure formation will be determined from comparison of the experimental data with the model predictions.As a result a series of new Al-based alloys with nanocomposite structure with improved mechanical properties and enhanced thermal stability will be developed and the fundamental basis for the nanostructured alloys design will be created. SUBJECT TERMS

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Effect of La on the crystallization behaviour of amorphous Al94−xNi6Lax (x=4–7) alloys

Cited by 70 publications

References 26 publications

Mechanical Properties and Nanocrystallization Behavior of Al-Ni-La Alloys

Mechanical Properties and Nanocrystallization Behavior of Al-Ni-La Alloys

Electrochemical response of amorphous and devitrified Al‐Ni‐La‐X (X = Ag, Cu) alloys

Development of High Strength Thermally Stable Al-based Alloys with Nanocomposite Structure

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