Experiment No.：201906073 (1 shift)

BL8S1

X-ray Diffraction study on W-Ni and Steel for 3D printing(Part 1 – W-Ni)(NSU – Aichi Pref. Joint Research Program)
Jun Ding 1, Osamu Fukuoka2, Takaaki Murai2,
Yasushi Uehara3, Yoshikazu Takeda3
1Nat. Univ. Singapore，2Aich Center for Industry & Sci. Tech., 3Aichi Synch. Rad. Center

keywords：X-ray diffraction，Amorphous structure，metallic materials，corrosion resistance
1．Introduction
Recently, we have prepared amorphous Ni-W samples. Amorphous metal materials have shown
many promising properties, including high yielding strength, chemical stability, ferromagnetic
behavior etc. The samples have shown interesting properties, such as high hardness and corrosion
resistance. The material might have potential in practical applications. In this work, we havestudied its microstructure, if it is indeed amorphous.

2．Experiment
Small plate shaped samples were used in the study. Fast scanning was used to check the position, 2 range,
and a rough estimation. After the fast scanning, the samples were measured under parameters for scanning in theideal 2 range for an accurate estimation

3．Results and Discussions
As shown in Figure 1, all the samples haveshown very similar XRD spectra.

There is avery broa peak in the range of 2 from 30 to 50
degree.

The broad peak confirms theamorphous structure [1]. All the samples haveshown similar structures, indicating good qualityof amorphous structure and uniformity of oursamples prepared.

4．References
1．J. Schroers, Acta Mat. 56 (2008) 471.
2．W. L. Johnson, JOM 54 (2002) 40.

Experiment No.：201906073-2 (1 shift)

BL 8S1

X-ray Diffraction study on W-Ni and Steel for 3D printing(Part 2 – 4340 Steel)(NSU – Aichi Pref. Joint Research Program)
Jun Ding 1, Osamu Fukuoka2, Takaaki Murai2,Yasushi Uehara3, Yoshikazu Takeda3
1Nat. Univ. Singapore，2Aich Center for Industry & Sci. Tech., 3Aichi Synch. Rad. Center
keywords：X-ray diffraction，Amorphous structure，metallic materials，corrosion resistance
1．Introduction
Recently, we have used selective laser melting for fabrication of 3D structures. Some interesting
results have been obtained, such as high tensile strength of 1600-1700 MPa and good ductility of 1216 %. In this work, we have used XRD to study their microstructures. The results confirmed thatretaining austenite phase was found, accompanied with relatively lower yielding strength. Our
further study has shown phase transformation into bcc (or martensite) after mechanical deformation.
2．Experiment
Small plates of 4340 steel were made by wire cutting.
XRD was carried out for the two samples. Some
unidentified peaks were found. New samples weremade by wire cutting followed by chemical etching. A
comparison study between before and after chemical
etching was done.
3．Results and Discussions
As shown in Figure 2, all the samples have shown very
similar XRD spectra measured at AichiSR BL8S1.
Both samples have shown a complex structure. Acloser study of these peaks at lower angles inciated thatthese peaks could be due to comtamination during thewire cutting process. After returing
Singpaore, we have examined thesmaple under SEM. EDAX study
showed contamination of Cu(because of copper wire used), Zn, Oand C, as shown in Fig. 3. In Fig.
3, we can see that there are two fcc
phases, one can be well idnetified asfcc Fe and another one is attributed
to fcc Cu. In a separate study, weused chemcial etching to remove thesurface.
After the chemcial
etching, all the XRD peaks below 2= 35 disappeared. As hsown in
Fig. 3, the XRD pattern after
chemical etching can be wellidnetified as a mixture of bcc and fcc
Fe. A roguh estinaton shows thepresence of approximately 10 wt%
of fcc Fe, confirming the presence ofaustenite phase in the as-printedstage.

Not identified