1. School of Mechanical Engineering，Anhui University of Technology, Ma'anshan 243002, China 2. Institute of Tribology, Hefei University of Technology, Hefei 230009, China
Cite this article:
ZHANG Guotao , YIN Yanguo , TONG Baohong , ZHANG Xingquan. Controllable Preparation and Self-Lubricating Mechanism Analysis of Bilayer Porous Iron-Based Powder Metallurgy Materials. Acta Metall Sin, 2019, 55(11): 1448-1456.
The bilayer porous material with dense substrate layer and variable porosity surface layer was prepared by powder metallurgy technology. TiH2 was used as the pore former to improve the oil content in the surface layer, and amide wax was used as a dense agent to increase the density and strength of the substrate. The microstructure, phases distribution and the worn surface morphology were characterized by SEM, EDS, XRD, etc. The tribological properties under boundary lubrication conditions were tested by end-face friction tester. The self-lubricating mechanism of single and bilayer sintered materials under different load conditions was analyzed by comparing their friction coefficients under the progressive loading friction test. Results show that adding TiH2 in the surface layer can effectively improve the porosity and oil ratio of the bilayer materials. Meanwhile, the hard particles TiC generated by the in-situ synthesis reaction have a hard reinforcing effect on the pore channel, which will improve the wear resistance and maintain steady the contact interface and lubrication state of the friction pair. The composite material containing 3.5%TiH2 has better mechanical and tribological properties. The looser surface layer of the composite material has a better oil self-lubricating property, and the dense substrate can effectively prevent the oil moving downward and keep the lubricant between the friction surfaces. So the comprehensive tribological and mechanical properties of the composite material are better than that of the single-layer material, which is suitable for heavy load or complex lubrication conditions.
Fund: National Natural Science Foundation of China Nos(51575151);National Natural Science Foundation of China Nos(51975005);and Natural Science Foundation of Anhui Province(1908085QE195)
Table 1 Formula of different TiH2 content (mass fraction / %)
Fig.1 Pores distribution of the materials with different contents of TiH2(a) 0% (b) 2% (c) 3% (d) 4%
Fig.2 Morphology in cross-section of sample (a) and linear scanning element distributions of Fe (b), Cu (c) and Ti (d)
Fig.3 SEM and EDS analyses of the surface layer of samples with TiH2 contents of 0% (a) and 3.5% (b, c) (Fig.3c is the local magnification of the area circled in Fig.3b; w—mass fraction, σ—error rate)
Fig.4 XRD spectrum of the material with 3.5%TiH2
TiH2 content
%
Oil ratio
%
Hardness HRB
Crushing strength
MPa
0
13.4
54
852
2
16.4
58
816
2.5
17.6
61
789
3
18.3
63
781
3.5
18.7
65
762
4
19.2
66
753
Table 2 Effect of TiH2 contents on the properties of surface layer materials
Fig.5 Effect of TiH2 content on tribological properties of bilayer materials under the progressive loading condition(a) friction coefficient(b) average friction coefficient(c) limit load and friction life
Fig.6 The morphologies of wear track in the variable load test with different contents of TiH2(a) 0% (b) 3.5% (c) 4.0%
Fig.7 Tribological properties of single-layer 7# and bilayer 5# specimens under variable load tests(a) friction coefficient(b) limit load and friction life(c) temperature
Fig.8 Self-lubrication mechanism of single-layer and bilayer sintered samples under light load (a) and heavy load (b) (Q1—oil flow of single-layer sample, Q2—oil flow of bilayer sample)
[1]
SongY P, GaoX, LiF D, et al. Study on self-sharpening cutters for forage harvesting machine with functionally gradient material prepared by combustion synthesis melt-casting under ultra-gravity field [J]. Sci. Sin. Tech., 2018, 48: 94
MartinF, GarcíaC, BlancoY. Influence of residual porosity on the dry and lubricated sliding wear of a powder metallurgy austenitic stainless steel [J]. Wear, 2015, 328-329: 1
[3]
CamposK R, KapsaP, BinderC, et al. Tribological evaluation of self-lubricating sintered steels [J]. Wear, 2015, 332-333: 932
[4]
ChengL, ChengJ G, ChenW C, et al. Effects of chromium addition forms on microstructure and properties of powder metallurgy sintering Fe-2Cu-3Cr-0.8Calloy [J]. Mater. Mech. Eng., 2019, 43: 47
PanY, LuX, LiuC C, et al. Effect of Sn addition on densification and mechanical properties of sintered TiAl base alloys [J]. Acta Metall. Sin., 2018, 54: 93
GuoR P, XuL, ChengW X, et al. Effect of hot isostatic pressing parameters on microstructure and mechanical properties of powder metallurgy Ti-5Al-2.5Sn ELI alloy [J]. Acta Metall. Sin., 2016, 52: 842
ZhengK H, GaoY M, ChenL, et al. Three-body abrasive wear behavior of iron matrix composites reinforced with tungsten carbide particles [J]. Tribology, 2012, 32: 176
LiuZ L, LiH H, LiuX Q, et al. Effect of warm compaction lubricant on the properties of Fe-based powder metallurgy materials [J]. Mater. Res. Express, 2019, 6: 1591
[10]
SharmaM, GuptaG K, DasguptaR, et al. Titanium foams processed through powder metallurgy route using lubricant acrawax as space holder material [J]. Trans. Indian Inst. Met., 2018, 71: 1933
[11]
RavindranP, ManisekarK, RathikaP, et al. Tribological properties of powder metallurgy—Processed aluminium self lubricating hybrid composites with SiC additions [J]. Mater. Des., 2013, 45: 561
[12]
HidalgoA A, FrykholmR, EbelT, et al. Powder metallurgy strategies to improve properties and processing of titanium alloys: A review [J]. Adv. Eng. Mater., 2017, 19: 1600743
[13]
MereibD, SeuU C C, ZakhourM, et al. Fabrication of biomimetic titanium laminated material using flakes powder metallurgy [J]. J. Mater. Sci., 2018, 53: 7857
[14]
ChenB, ShenJ H, YeX X, et al. Advanced mechanical properties of powder metallurgy commercially pure titanium with a high oxygen concentration [J]. J. Mater. Res., 2017, 32: 3769
[15]
XuanZ, WangM J, FuY F, et al. Effect of borides on hot deformation behavior and microstructure evolution of powder metallurgy high borated stainless steel [J]. Mater. Charact., 2017, 124: 182
[16]
JinG, TakeuchiM, HondaS, et al. Properties of multilayered mullite/Mo functionally graded materials fabricated by powder metallurgy processing [J]. Mater. Chem. Phys., 2005, 89: 238
[17]
Wi?niewska-WeinertH. Deposition of MoS2 particulate layers by pressure impregnation of porous sliding bearings [J]. Arch. Civil Mech. Eng., 2014, 14: 255
[18]
MouriT, SugaiY, ItoY, et al. Strength and friction-wear properties of complex layer bearing via unification powder forming and sintering process [J]. J. Jpn. Soc. Powder Powder Metall., 2015, 62: 371
Vida-SimitiI, JumateN, ThalmaierG, et al. Sintering of sedimented nickel powder gradual porous structures [J]. Powder Metall., 2012, 55: 154
[20]
ChengM. Research on the microstructure and mechanical properties of double-layer iron-based powder metallurgy material [D]. Nanjing: Nanjing University of Science and Technology, 2013
[20]
程 敏. 双层铁基粉末冶金材料组织与性能研究 [D]. 南京: 南京理工大学, 2013
[21]
ZhangG T, YinY G, XuM, et al. Tribological properties and mechanism of the bilayer iron based powder metallurgy materials [J]. Ind. Lubr. Tribol., 2018, 70: 1642
[22]
KagoharaY, TakayanagiS, HanedaS, et al. Tribological property of plain bearing with low frictional layer [J]. Tribol. Int., 2009, 42: 1800
[23]
übeyliM, BalciE, SarikanB, et al. The ballistic performance of SiC-AA7075 functionally graded composite produced by powder metallurgy [J]. Mater. Des., 2014, 56: 31
[24]
ZhangH Y, JinH, WangJ J, et al. Development of a path planning algorithm for reduced dimension patch printing conductive pattern on surfaces [J]. Int. J. Adv. Manuf. Technol., 2017, 95: 1645
[25]
ZhangG T, YinY G, LiuZ M, et al. Tribological properties of multi-layer iron based powder metallurgy materials [J]. Trans. Mater. Heat Treat., 2017, 38: 7
