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S L Mannan - One of the best experts on this subject based on the ideXlab platform.

  • influence of temperature on the low cycle fatigue behaviour of a modified 9cr 1mo ferritic steel
    International Journal of Fatigue, 2002
    Co-Authors: A Nagesha, M Valsan, R Kannan, Bhanu Sankara K Rao, S L Mannan
    Abstract:

    Abstract Low cycle fatigue (LCF) behaviour of a modified 9Cr–1Mo steel under normalized and tempered conditions is reported. The alloy was normalized at 1313K for 1 h followed by tempering at 1033K for 1 h, which resulted in a tempered Martensitic Structure. Total axial strain controlled LCF tests were conducted at a constant strain rate of 3×10 −3 s −1 at different strain amplitudes varying from ±0.25 to ±1.0% in the temperature range of 300–873K. The cyclic stress response behaviour, in general, showed an initial brief hardening for the first few cycles, followed by a continuous and gradual softening regime that ended in a stress plateau that continued up to the specimen failure. The fatigue life decreased as the temperature increased. The temperature effect on life was more pronounced at low strain amplitudes. The metallography of the failed samples revealed that the fatigue failure at high amplitudes of testing was marked by extensive crack branching and the formation of secondary cracks. Oxidation was found to exert major influence on LCF life reduction at 873K.

  • microStructure and tensile properties of modified 9cr 1mo steel grade 91
    Materials Science and Technology, 2001
    Co-Authors: K S Chandravathi, Bhanu Sankara K Rao, K Laha, S L Mannan
    Abstract:

    AbstractThe influence of different soaking temperatures in the range 973–1623 K (below Ac 1 to above Ac 4) before oil quenching and tempering, on the microStructure, hardness, grain size, and tensile properties of modified 9Cr–1Mo steel has been studied. This was done in an effort to assess the tensile behaviour of the different microStructures likely to be encountered in the heat affected zone of a fusion welded joint of the steel. The steel developed predominantly Martensitic Structure after quenching. Soaking of steel in the intercritical temperature range (between Ac 1 and Ac 3) reduced the prior austenitic grain size and hardness. Soaking temperatures above Ac 3 increased the grain size and hardness of the steel until the formation of δ ferrite at temperatures above Ac 4. The δ ferrite formation at soaking temperatures above Ac 4 reduced the grain size and hardness of the steel. The tensile strength of the steel exhibited a minimum for soaking in the intercritical temperature range where the ductilit...

C P Ju - One of the best experts on this subject based on the ideXlab platform.

  • Structure and properties of cast binary ti mo alloys
    Biomaterials, 1999
    Co-Authors: W F Ho, C P Ju
    Abstract:

    Structure and properties of a series of binary Ti–Mo alloys with molybdenum contents ranging from 6 to 20 wt% have been investigated. Experimental results indicated that crystal Structure and morphology of the cast alloys were sensitive to their molybdenum contents. The hexagonal α′ phase c.p. Ti exhibited a feather-like morphology. When Mo content was 6 wt%, a fine, acicular Martensitic Structure of orthorhombic α″ phase was observed. When Mo content was 7.5 wt%, the entire alloy was dominated by the Martensitic α″ Structure. When Mo content was increased to 10 wt% or higher, the retained β phase became the only dominant phase. Among all Ti–Mo alloys, the α″ phase Ti–7.5Mo alloy had the lowest hardness. The bending strength of Ti–7.5Mo was similar to that of Ti–15Mo and Ti–13Nb–13Zr, and higher than c.p. Ti by nearly 60%. The bending modulus of the α″-dominated Ti–7.5Mo alloy was lower than that of Ti–15Mo by 22%, of Ti–6Al–4V by 47%, of Ti–13Nb–13Zr by 17%, and of c.p. Ti by 40%.

J Chern H Lin - One of the best experts on this subject based on the ideXlab platform.

  • Structure and properties of cast binary ti mo alloys
    Biomaterials, 1999
    Co-Authors: J Chern H Lin
    Abstract:

    Structure and properties of a series of binary Ti–Mo alloys with molybdenum contents ranging from 6 to 20 wt% have been investigated. Experimental results indicated that crystal Structure and morphology of the cast alloys were sensitive to their molybdenum contents. The hexagonal α′ phase c.p. Ti exhibited a feather-like morphology. When Mo content was 6 wt%, a fine, acicular Martensitic Structure of orthorhombic α″ phase was observed. When Mo content was 7.5 wt%, the entire alloy was dominated by the Martensitic α″ Structure. When Mo content was increased to 10 wt% or higher, the retained β phase became the only dominant phase. Among all Ti–Mo alloys, the α″ phase Ti–7.5Mo alloy had the lowest hardness. The bending strength of Ti–7.5Mo was similar to that of Ti–15Mo and Ti–13Nb–13Zr, and higher than c.p. Ti by nearly 60%. The bending modulus of the α″-dominated Ti–7.5Mo alloy was lower than that of Ti–15Mo by 22%, of Ti–6Al–4V by 47%, of Ti–13Nb–13Zr by 17%, and of c.p. Ti by 40%.

T Kurennykh - One of the best experts on this subject based on the ideXlab platform.

  • oxygen and nitrogen concentrations in the ti 6al 4v alloy manufactured by direct metal laser sintering dmls process
    Materials Letters, 2017
    Co-Authors: N Kazantseva, Pavel Krakhmalev, I Yadroitsev, A Fefelov, A G Merkushev, M Ilyinikh, N I Vinogradova, I Ezhov, T Kurennykh
    Abstract:

    Abstract Two machines from two scientific centers (Russia and South Africa) were used for the manufacturing of the Ti6Al4V alloys by the direct metal laser sintering. The chemical composition of powders complies with the ASTM F-136 (grade 5), ASTM B348 (grade 23) standard for medical applications. Analysis of the oxygen and nitrogen contamination in DMLS alloys was done with Van de Graaff accelerator with two Mega Volts. It is found that Structures of the samples manufactured with two different machines used the same regimes are close to each other. TEM studies found the metastable Martensitic Structure and silicon nitride Si3N4. It was found that the oxygen and nitrogen contents in both samples are within the normal range for medical grade titanium alloys.

Kurennykh T. - One of the best experts on this subject based on the ideXlab platform.

  • Oxygen and nitrogen concentrations in the Ti-6Al-4V alloy manufactured by direct metal laser sintering (DMLS) process
    Materials Letters, 2017
    Co-Authors: Kazantseva N., Krakhmalev P., Fefelov A., Merkushev A., Ilyinikh M., Inogradova N., Kurennykh T.
    Abstract:

    Published ArticleTwo machines from two scientific centers (Russia and South Africa) were used for the manufacturing of the Ti6Al4V alloys by the direct metal laser sintering. The chemical composition of powders complies with the ASTM F-136 (grade 5), ASTM B348 (grade 23) standard for medical applications. Analysis of the oxygen and nitrogen contamination in DMLS alloys was done with Van de Graaff accelerator with two Mega Volts. It is found that Structures of the samples manufactured with two different machines used the same regimes are close to each other. TEM studies found the metastable Martensitic Structure and silicon nitride Si3N4. It was found that the oxygen and nitrogen contents in both samples are within the normal range for medical grade titanium alloys