Morphology and formation mechanism of equiaxed grains along the fusion boundary in Al–Li alloy weld seam

TA15/Ti2AlNb multiple-layer samples and a dual-alloy sample were fabricated by laser solid forming (LSF) in this study. The formation mechanism of the dilute region and microstructure evolution of the dual alloy were analyzed. The results confirmed a “step” distribution of the composition among several initial layers in the multiple-layer samples, which can be explained by calculating the ratio of the remelted zone to the deposited Ti2AlNb zone in each deposited layer. However, the “step” compositional distribution disappears, and the compositional variation tends to be more continuous and smooth in the TA15/Ti2AlNb dual-alloy sample, which is attributed to alloy elements’ diffusion at the subsequent multiple re-melting and the longer thermal cycle. The macrostructure of the TA15/Ti2AlNb dual-alloy sample consists of epitaxially grown columnar prior β grains at the TA15 side and equiaxed grains at the Ti2AlNb side, while the microstructure shows a transition of α+β→α+α2+β/B2→α2+β/B2→α2+B2+O with increasing amounts of Ti2AlNb, leading to the microhardness also changing significantly.

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Microstructure homogenization of 2A14 aluminum alloy weld seam by ultrasonic irradiation in metal inert gas welding

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-019-04784-x ◽

2020 ◽

Vol 108 (4) ◽

pp. 1085-1089 ◽

Cited By ~ 1

Author(s):

Chenglei Fan ◽

Chao Chen ◽

Sanbao Lin ◽

Zeng Liu ◽

Xiaoyu Cai ◽

...

Keyword(s):

Aluminum Alloy ◽

Ultrasonic Irradiation ◽

Weld Seam ◽

Inert Gas ◽

Metal Inert Gas Welding ◽

Alloy Weld

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Comparison of Al-Zn-Mg Alloy P-MIG Welded Joints Filled with Different Wires

High Temperature Materials and Processes ◽

10.1515/htmp-2017-0146 ◽

2019 ◽

Vol 38 (2019) ◽

pp. 516-524

Author(s):

Wang Dianlong ◽

Diao Guangyun ◽

Liang Zhimin

Keyword(s):

Mechanical Properties ◽

Grain Size ◽

Cross Section ◽

Welded Joints ◽

Mg Alloy ◽

Mig Welding ◽

Fusion Boundary ◽

Alloy Plate ◽

Microhardness Test ◽

Equiaxed Grains

AbstractThree kinds of welding filler wires, named ER5356, ER5087 and ER4043, were used to joint 12 mm thick Al-Zn-Mg alloy plate by the pulsed MIG(P-MIG) welding. The microstructure and mechanical properties of the joints were analyzed and compared. The results showed that the average tensile strengths of the joints filled with ER5356, ER5087 and ER4043 were 294 MPa, 313 MPa and 237 MPa, respectively, and the average elongations were 7.9%, 7.6% and 1.6%, respectively. All the joints’s fracture locations were near the fusion boundary. The microhardness test showed that the locations of the lowest hardness were all in the center of cross section. The results revealed that the weld filler by ER5087 was consist of more columnar crystals of larger grain size, while the weld filled by ER5356 was consist of more equiaxed grains of smaller grain size. The microstructure of the weld by ER4043 was typical eutectic dendrites structure.

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A Model for Predicting Weld Metal Grain Refinement in G-V Space

MRS Proceedings ◽

10.1557/proc-578-431 ◽

1999 ◽

Vol 578 ◽

Cited By ~ 5

Author(s):

Ø. Grong ◽

C.E. Cross

Keyword(s):

Growth Rate ◽

Weld Metal ◽

Grain Refinement ◽

Graphical Representation ◽

Nucleation Site ◽

Grain Structure ◽

Fusion Boundary ◽

Site Density ◽

Equiaxed Grains ◽

Nucleation Site Density

AbstractA model has been developed which allows for the graphical representation of undercooling and nucleation site density in G-V space (i.e. temperature gradient G versus growth rate V). This model is used to explain a unique grain structure in weldments where equiaxed grains may be found both at the fusion boundary and along the center of the weld metal. Details of this model will be given and discussed in relation to grain refinement predictions in G- V space.

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