Microstructure evolution and layer bands of laser melting deposition Ti–6.5Al–3.5Mo–1.5Zr–0.3Si titanium alloy

Zhu, Yanyan; Tian, Xiangjun; Li, Jia; Wang, Huaming

doi:10.1016/j.jallcom.2014.07.161

Cited by 132 publications

(28 citation statements)

References 28 publications

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“…and the thermal history may have determined the microstructural development and thus any processing parameter that would affect the energy density and thermal history may show influence on microstructure. This is consistent with previous studies [8,13,14,17] which also suggest that the microstructural development of Ti-alloys is highly dependent on thermal history. Another microstructural characteristic for the current as-fabricated Ti5553 samples is the precipitation of a phase at the very bottom region, which may be attributed to the continuous self-annealing effect due to heat sink down to the bottom region during fabrication.…”

Section: Discussionsupporting

confidence: 93%

“…Extensive study has been performed on these alloys in terms of structural integrity (e.g. porosity) [3][4][5], geometric integrity [3], microstructure [3][4][5][6][7][8][9][10][11][12][13][14], residual stress [15], distortion [3,15], mechanical properties and anisotropy [3,5,10,12] and the influence of laser processing condition and post-build heat treatment and hot isostatic pressing [3,5,16]. Throughout these studies, it is well understood that these alloys are liable to development of porosity especially lack-of-fusion pores at the inter-layer boundaries during DLD which are blamed for tensile anisotropy [3,5].…”

Section: Introductionmentioning

confidence: 99%

“…Throughout these studies, it is well understood that these alloys are liable to development of porosity especially lack-of-fusion pores at the inter-layer boundaries during DLD which are blamed for tensile anisotropy [3,5]. Also, these alloys tend to develop columnar grains and strong texture after DLD [3,6,10,13].…”

Section: Introductionmentioning

confidence: 99%

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Microstructural control during direct laser deposition of a β-titanium alloy

2015

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a b s t r a c tA concern associated with Direct Laser Deposition (DLD) is the difficulty in controlling microstructure due to rapid cooling rates after deposition, particularly in beta-Ti alloys. In these alloys, the beta-phase is likely to exist following DLD, instead of the desirable duplex alpha + beta microstructure that gives a good balance of properties. Thus, in this work, a parametric study was performed to assess the role of DLD parameters on porosity, build geometry, and microstructure in a beta-Ti alloy, Ti-5Al-5Mo-5V-3 Cr (Ti5553). The builds were examined using optical microscopy, scanning electron microscopy, and X-ray diffraction. Microhardness measurements were performed to assess the degree of re-precipitation of alpha-phase following an in situ dwelling and laser annealing procedure. The study identified several processing conditions that enable deposition of samples with the desired geometry and low porosity level. The microstructure was dominated by beta-phase, except for the region near the substrate where a limited amount of alpha-precipitates was present due to reheating effect. Although the microstructure was a mixture of equiaxed and columnar beta-grains alongside infrequent fine alpha-precipitates, the builds showed fairly uniform microhardness in different regions. In situ dwelling and annealing did not cause an obvious change in porosity, but did promote the formation of alpha-precipitates.

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Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

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Microstructural control during direct laser deposition of a β-titanium alloy

2015

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“…A number of studies have been carried out in the literature to understand the influence of processing parameters on the economy and properties of laser metal deposited materials [11][12][13][14][15][16]. In this study, the influence of powder flow rate on the microstructure and microhardness of laser metal deposited Ti6Al4V.…”

Section: Introductionmentioning

confidence: 99%

Influence of Powder Flow Rate on Properties of Laser Deposited Titanium Alloy -Ti6Al4V

Mahamood¹,

Akinlabi²

2017

Proceedings of the Second International Conference on Mechanics, Materials and Structural Engineering (ICMMSE 2017)

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Abstract. Titanium alloy-Ti6Al4V is an important aerospace alloy with excellent properties but it is classified as difficult to machine material that requires an alternative manufacturing process. Laser metal deposition process is an ideal alternative manufacturing process that can offset most of the problem encountered while processing the alloy using the traditional manufacturing method. Processing parameter play an important role in the resulting properties of material processed using the laser metal deposition process. The key processing parameters that have significant influence in the properties of the processed material in laser metal deposition process include laser power, scanning speed, powder flow rate and gas flow rate. In this study, the effect of powder flow rate on the evolving microstructure and microhardness of Ti6Al4V using the laser metal deposition process is investigated. The laser power, scanning speed and powder flow rate were kept constant while the powder flow rate was varied between 1.44 g/min and 7.2 g/min. The results showed that the microhardness increased as the powder flow rate was increased. The microstructure was found to change from coarse Widmanstätten alpha to coarse martensitic alpha as the powder flow rate was increased. This study is important to know the required powder flow rate to be employed in order to achieve the desired properties during building of new part as well as repair.

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“…Within three groups of cladding materials including Ni-based, Co-based and Fe-based powders, Ni-based powder has higher hardness [12]. It was known that Ni-Cr-B-Si powder has been widely cladded on steel substrate [13], aluminum substrate [14] and titanium substrate [15,16]. Xuan et al [13] prepared Ni-Cr-B-Si coatings on carbon steels and revealed microstructure and flame erosion mechanism.…”

Section: Introductionmentioning

confidence: 99%