Title: SUPPLEMENTARY INFORMATION. Gradient Confinement Induced Uniform Tensile Ductility in Metallic Glass

Transcription

1 SUPPLEMENTARY INFORMATION Title: Grdient Confinement Induced Uniform Tensile Ductility in Metllic Glss X.L. Lu 1, Q.H. Lu 1, Y. Li* 1,2 nd L. Lu* 1 1 Shenyng Ntionl Lortory for Mterils Science, Institute of Metl Reserch, Chinese Acdemy of Sciences, 72 Wenhu Rod, Shenyng, , P.R. Chin 2 Deprtment of Mterils Science nd Engineering, Fculty of Engineering, Ntionl University of Singpore, Singpore Correspondence nd requests for mterils should e ddressed to: L.L (llu@imr.c.cn); Y. L (liyi@imr.c.cn) 1

2 1. Mterils nd grdient nno-grined (GNG) smple preprtion Surfce mechnicl grinding tretment (SMGT) 1 ws used to synthesize grdient nno-grined (GNG) surfce lyer on corse grin (CG)Ni sustrte. Commercil CG Ni with purity of 99.7% ws cut into dog-one-shped tensile r with guge dimeter of 6mm nd length of 30mm of which the geometry is indicted in Fig. S1, nd then susequently nneled t 700 C for 6h for fully recrystllizion microstructure. The verge grin size of the s-nneled Ni is out19 m. Then the tensile rs were processed y mens of SMGT t room temperture. The SMGT processing prmeters re s follows: rotting velocity of the smple v1=300 rpm, sliding velocity of the tool tip v2 = 30 mm min -1, the preset penetrtion depth of the tooltip into the smple p = 30 m. A hemi-sphericl WC/Co tool tip (with rdius of r = 5 mm) ws used. For ech smple, the SMGT process ws repeted twelve times with the sme processing prmeters for chieving thick nd uniform GNG lyer. Plstic deformtion is rther uniform in the surfce lyer nd the surfce is shining nd smooth with smll surfce roughness (R 0.15 m). No crck ws identified in the surfce of the SMGT processed smples. 2. Ni-P film deposition Electroless deposition of the Ni-P morphous coting on the GNG Ni sustrtes ws processed y immersing the tension r smples in hypophosphte th. The detil of the chemicl composition is s follows: 20 g/l nickel sulfte, 30 g/l sodium hypophosphite, 30 g/l sodium cette,12.5 ml/l lctic cid, nd 1 mg/l led cette. The solution ws mintined t ph vlue of 4.5~5.0, temperture of 85±2 C nd deposition time of 30 min. The thickness of the Ni-P film is out 6 μm mesured from the cross-sectionl SEM imge. The XRD result shows typicl rod pek indictes the mophicity of Ni-P film (s indicted in Figure S2, which is consistent with the previous studies tht the structure is in morphous stte with high phosphorous content (8-14 wt. %) 2-4. The chemicl content of the Ni-P morphous is: P is 9.57 wt. % nd Ni is 90.43wt.%, s indicted y the EDX nlysis in Figure S2. 3. Tensile tests 2

3 Unixil qusi-sttic tensile tests were performed in n Instron 8801Testing System (MTS) t mient temperture nd strin rte of 2.5x10-5 s -1. A clip-on extensometer ws used to clirte nd mesure the strin of the smples upon tensile. 4. XRD, TEM, SEM,EDX, CLSM experiments X-ry diffrction (XRD) mesurements were crried out on the smple surfce using Rigku DMAX/2400 X-ry diffrctometer with Cu K rdition. Trnsverse sectionl Ni-P morphous nd Ni sustrte interfce were chrcterized y trnsmission electron microscope (TEM) imges using n FEI Tecni G 2 20 t n ccelerting voltge of 200 KV. The top surfces of smples were exmined in FEI Nov NnoSEM 430 field emission gun scnning electron microscope (SEM) with secondry electron imging nd the cross-sectionl chrcteriztion ws crried out with electron-chnneling contrst (ECC) imging using VCD detector. Energy Dispersive X-ry nlysis (EDX) were crried out on Oxford INCA X-ct fixed on SEM 430.The sher nds on the surfce fter tensile tests were detected y using n Olympus 4000 confocl lser scnning microscope (CLSM). The height resolution in Z xe is 10 nm. 5. Supplementry Figures S1-S5 Figure S1. Illustrtion of the tensile r smple geometry. The lue re indicted the GNG region deformed y SMGT process. The guge dimension is Φ6 30 mm. Element Weight% Atomic% P K Ni K Figure S2. XRD nd EDX nlysis of the s-deposited Ni-P film 3

4 Figure S3. Engineering tensile stress-strin curves of GNG Ni with Ni-P film with different strins (5%, 10%, 12.5% nd 15%, s indicted in the Figures),respectively. The slight differences mong the s-s curves come from the depth vrition of top GNG lyer in SMGT processing nd the guge size mesurement error. Tensile direction 200 nm c d 4 200

5 Figure S4. A cross-sectionl structure of GNG structures efore tension test. SEM imge () nd TEM imge () of the GNG structure just eneth the Ni-P morphous film. An elongted grin morphology, which is prllel to the tensile loding direction, ws clerly seen fter SMGT process. The grin size distriutions from TEM mesurements re sttisticlly shown from trnsverse direction in (c) nd from longitudinl direction in (d). The longitudinl xe is defined s the longest chord in one grin, which mostly prllel to tensile direction in (). And the trnsverse xe is the verticl direction of the longitudinl direction. Figure S5. The grin size distriutions of the GNG lyer from TEM mesurements fter tension test. (Figs. 4&) re sttisticlly shown from trnsverse direction in () nd from longitudinl direction in ().The sttisticl dt counted from 236 grins. The grin size distriutions re roughly comprle for the GNG lyers efore nd fter 15% tensile strin, from oth the trnsverse direction nd longitudinl direction. The interfce ecme rougher compred to tht efore tension (Fig S4.), yet the film is still dhered firmly to the sustrte nd no delmintion ws oserved. References: 1 Li, W. L., To, N. R. & Lu, K. Friction of grdient nno-micro-structured surfce lyer on ulk copper y mens of surfce mechnicl grinding tretment. Scr. Mter. 59, , (2008). 2 Goldenstein, A. W., Rostoker, W., Schosserger, F. & Gutzeit, G. Structure of chemiclly deposited nickel. J. Electrochem. Soc. 104, , (1957). 3 Allen, R. M. & VnderSnde, J. B. The structure of electroless ni---p films s function of composition. Scr. Metll. 16, , (1982). 4 Keyse, R. J. & Hmmond, C. Structure nd morphology of electroless ni-p deposits. Mter. Sci. Technol.-lond. 3, , (1987). 5