Fracture Toughness of Recycled AISI 1040 Steel Chip Reinforced

si b,

recys oftieslumatr

iors of composites, compressive strength, three point bending, hardness and fracture toughness, initialnotch depth method tests were performed at ambient condition. It was observed that steel chip rein-

1. Introduction

by porecentacturins come

scrap, approximately 10% of it is burst and approximately 10%of it is lost on account of aluminum waste and scraps with theslag removed from surface of the ladle [4]. The reason for the sub-stantial losses of aluminum and aluminum alloys waste is due tothe rather long period of time in which it remains on the surface

Mg and W mate-ined thatnversion mption and

The reinforcement of FeCr showed very good mechanical proper-ties at room and elevated temperatures. Chmura et al. [7] studiedthe recycling of aluminum and aluminumbronze chip in the useof bearings. Bearing composites were produced by cold compactionand hot extrusion. Mechanical and tribological properties weredetermined for end of production processes of composite bearingsamples, and it was found aluminum-based with aluminum bronzereinforcing phase have better frictional properties. Corresponding author. Tel.: +90 332 223 1907; fax: +90 332 241 01 56.

Materials and Design 52 (2013) 345352

Contents lists available at

an

elsE-mail address: [email protected] (M. Turan Demirci).metals and their alloys [3].In the melting process for recycling aluminum waste and

material savings. Gronostajski et al. [4] investigated aluminumchip composites and used the FeCr powder as a reinforcing phase.sisting in the direct conversion of chip into compact metal. Oneof them contains granulation which remains after cutting process,then cold pressing and sintering processes. This type of recyclingcan be applied to iron, copper, aluminum, to some extent to cast

hot extrusion. As aluminum alloys, they used Cu,rials. As a result of their experiments, they determnum and its alloys can be recycled by a direct cowhich is characterized by low energy-consum0261-3069/$ - see front matter 2013 Elsevier Ltd. All rights reserved.http://dx.doi.org/10.1016/j.matdes.2013.05.025alumi-ethodlargeIn metal industries, waste and scrap metals that remain aftermanufacturing processing are chip and discards. These wastematerials are reutilized by returning them to smelters. However,during melting processes of materials for recycling, many metalsare lost due to occurring oxidation and costs of labor, energy andenvironmental protection expenditures [2]. To overcome these dis-advantages, there are different ways of recycling metal chip, con-

the cold pressing conditions. For obtaining optimum size andshape of the chip, they must be broken into to small pieces bymilling processes.

Gronostajski et al. [5] investigated new methods for aluminumand aluminum alloy chip recycling and compared conventionaland direct methods. Gronostajski et al. [6] in their study used thedirect recycling method which contains cold press molding andManufacturing sintered productsod has been developed gradually inthe recycling technologies for manufof waste products in metal industrieforcement provided increased compressive strength and hardness, but the fracture toughness of compos-ites decreased versus to increasing steel content. Considering analyses of microscopic micrographs ofcomposites (SEM), by increasing steel content causes an increase in the angular facets on fracturesurfaces.

2013 Elsevier Ltd. All rights reserved.

wder metallurgy meth-years. Especially, wheng have progressed, uses into prominences [1].

as molten aluminum and oxidizes intensively [2]. Therefore, pow-der methodology containing cold pressing and sintering processescan be used to overcome all the disadvantages of recycling of alu-minum waste chip. Aluminum chip especially are derived frommachining operations. For cold pressing and sintering, chip sizeand irregular elongated spiral shapes make them unsuitable toTechnical Report

Fracture toughness of recycled AISI 1040AlMg1SiCu aluminum chip composites

Reshad Guluzade a, Ahmet Avc a,, M. Turan Demirca Selcuk University, Mechanical Engineering Dep., Konya, Turkeyb Selcuk University, Mechanical Education Dep., Konya, TurkeycGaziantep University, Gaziantep Technical College, Gaziantep, Turkey

a r t i c l e i n f o

Article history:Received 21 February 2013Accepted 10 May 2013Available online 24 May 2013

a b s t r a c t

In this paper, a method ofology. This method consisttion of mechanical propermaterials and AlMg1SiCu ament was added into the m

Materials

journal homepage: www.teel chip reinforced

. Faruk Erkendirci c

cling aluminum and steel chip is presented by applying powder method-the composite production, cold pressing, a new sintering method, deni-and fracture toughness. AISI 1040 steel chip was used as reinforcementinum chip were used as matrix materials. AISI 1040 steel chip reinforce-ix for 20%, 30% and 40% weight ratios. To determine the mechanical behav-

SciVerse ScienceDirect

d Design

evier .com/locate /matdes

A single acting hydraulic press was used for compaction. Two dif-ferent types of compaction dies were used during the production ofcompressive and three point bending test specimens (Fig. 1).

Sintering characteristics were investigated in a laboratory fur-nace in 650 C and for 2 h under pure nitrogen atmosphere [8].All composites were heated to reach sintering temperatures atthe heating rate of 5 C/min and furnace cooled at room tempera-ture. After sintering process, microstructures of the composite

Materials Tensile strength (MPa) Elongation (%) Elast

8.910

andAbdizadeh et al. [8] studied aluminumzircon composites bypowder metallurgy method. The cold pressed composites were sin-tered at two different temperatures, 600 and 650 C. Then they car-ried out compressive and hardness tests. The best bondingtemperature was obtained at 650 C. They reached that adding zir-con particulates increased mechanical properties of composites.Zhao et al. [9] produced AlNi composites by powder metallurgyand examined mechanical properties such as microhardness, ulti-mate tensile strength and elongation. McKie et al. [10] Researchedmechanical properties of cubic boron nitride and aluminum com-posites which were produced by powder methodology. In thismethodology, they applied to high pressure and high temperaturesintering methods. After their experiments, they reached theimportant issues that the grain sizes affected the bonding of mate-rials. Showaiter and Yousef [11] examined the mechanical prop-erties of 6061 Al and Pb, Ag and Sn added 6061 Al composites.They determined the optimum sintering temperature was 620 Cand 1 h. under pure nitrogen for compaction pressures of 340and 510 MPa. Fogagnolo et al. [12] focused on the recycling of alu-minum alloy (Al2O3 recycled) and aluminum matrix (AA6061)composite chips by cold pressing and hot pressing. They were com-pared and reported that the higher oxidation of composites thatwas stemmed from the end of machining process of chip.

The aim of this work was to investigate the compaction, newsintering method and mechanical properties of composites pro-duced by AlMg1SiCu aluminum chip and reinforcement materialsof AISI 1040 steel chip attained at the end of the manufacturingprocesses (milling and turning) for recycling these materials. Manystudies for aluminum chip composites are concentrated on com-pression, hardness and wear properties to determine the mechan-ical properties. However, was not focused on fracture toughness ofthese composites. In this study, the fracture toughness of thesecomposites was investigated, and the new sintering method was

AlMg1SiCu 310 1416 6AISI 1040 620 25 (in 50 mm) 2Table 1Chemical composition of AlMg1SiCu aluminum and AISI 1040 steel chip.

Si (%) Fe (%) Cu (%) Mn (%)

AlMg1SiCu 0.67 0.74 0.123 0.138AISI 1040 0.2 98.6 0.65

Table 2Mechanical properties of AlMg1SiCu and AISI 1040.

346 R. Guluzade et al. /Materialsapplied to the composites for prevention of oxidation on AISI1040 steel and AlMg1SiCu aluminum chip border lines. In addition,occurrence oxidation on border lines was observed through SEManalyses.

2. Experimental details

2.1. Raw materials

AlMg1SiCu aluminum chip was used as the matrix and AISI1040 steel chip were used as reinforcing phase for the compositematerials. Chemical compositions, mechanical properties and frac-ture toughness were given in Tables 1 and 2 respectively. At thebeginning of the study, size reduction processes by using a cuttingdevice and sieve shaker were applied to aluminum and steel chipwhich are remaining materials from sawing process. Then, thesizes of the chip were reduced to grain sizes between 0.5 and2.2. Compaction and sintering

All mixture ratios given in Table 3 for compressive and threebending specimens were pressed at 250 MPa by using cold pressdie which was produced in accordance with ASTM E9-09 and ASTME290-09. Zinc stearate was used on the die wall and punches forlubrication before compaction to reduce die wall frictional effects.1 mm. Methyl alcohol was used to clean the chip from impuritiesand cutting oils were used as lubricants and coolant. The cleanedchips were dried at a temperature of 80 C in an oven for 2 h. Alu-minum chip used as matrix material was mixed with 2040 wt%ratios of reinforcing phase by mechanical stirrer for 15 min each(Table 3) and so three different kinds of compositions were pro-duced according to steel weight (%) contents.

Mg (%) Al (%) C (%) P (%) S (%)

1.26 96.7 0.4 0.04 0.2

Table 3Chip fraction used for this experiment.

Specimen Steel weight (gr) % Aluminum weight (gr) %

A 21 20 49 80B 28 30 42 70C 35 40 35 60

icity (GPa) Fracture toughness (MPa

Mp

) Hardness (Brinell)

29 9554 201

Design 52 (2013) 345352material surfaces in Fig. 2 were investigated to detect the sinteringtemperature and macro size sintering fault. For the sintering ofcomposites, sand and clay were used to prevent the oxidation ofaluminum chip in the sintering tube. In this method, the sand alsoserved to homogeneously heat the composites and prevented oxi-dations by absorbing metal gasses and humidity. First, cold pressedcomposites placed in a sintering tube in this new sintering method.Second, the sand lled with tubes and clay was used to close thetube mouth. The sintering tube seen in Fig. 3 held the gases whichwere released from composites.

Brinell hardness values of specimens were measured on the pol-ished surfaces of specimens using with a ball 5 mm diameter undera load of 250 kgf by holding 30 s [8]. For each specimen, ve hard-ness tests on randomly selected regions were performed in orderto eliminate the possible segregation effects and get a representa-tive value of the matrix material hardness. The compressive andthree bending tests to determine the compressive strength andfracture toughness were conducted in air at room temperature

andR. Guluzade et al. /Materialsaccording to ASTM E9-09 and ASTM E399-12 respectively (Figs. 4and 5). Three specimens were tested for each steel content.

Fracture toughness (Kc) of composite specimens was deter-mined by using the initial notch depth method in terms of ASTM

Fig. 2. Microstructure photographs of the composite

(a) compressive specimensFig. 1. Specimen product

Fig. 3. Sintering tube for specimens.(b) three bending specimension compaction dies.

Design 52 (2013) 345352 347E399-12. The fracture toughness Kc was calculated by given belowformula:

K1c rpaf a=W 1where r is the stress, a is an initial notch depth, f (a/W) is a geom-etry factor. In addition, to calculate the geometry factor Eq. (2)which given in ASTM were facilitated [13]. In this study, three dif-ferent (a/W) notch depth ratios were applied to composites todetermine the changing fracture in terms of different a/W notchdepths (0.085, 0.095 and 0, 1) and the average fracture toughnesswere found and discussed for all steel contents,

f a=W 1:93 3:07a=W 14:53a=W2 25:11a=W3

25:80a=W4 2The stress was determined from the following equation:

r 3PS=2BW2 3where P is critical load, S is the span, B is the specimen thicknessand W is the width of specimen.

3. Results and discussion

Increasing the weight of AISI 1040 steel chip, causes an increasein the density of specimens. The differences of theoretical and

material surfaces after sintering process (15X).

and348 R. Guluzade et al. /Materialssintered density of composites are very obvious, give in Fig. 6. Highsintering temperatures provide to the easier diffusion of atomswhich helps the better sintering of composites decrease the poros-ities of composites. Therefore, the density of composites reaches toa higher value [8,14].

The hardness of specimens has been tested by the Brinell mea-sure method. The results were presented at Fig. 7. The hardness ofspecimens was increased with rising steel weight (%) contents [8].The highest hardness values were observed on the surfaces of60%Al40%AISI1040 composites. In this study, hardness was

(a) Compressive test fixtureFig. 4. Compressive and three p

(a) 80%Al20%AISI1040

(c) 60%Al40%

Fig. 5. Instant photographs of failDesign 52 (2013) 345352compared with hardness values obtained from study of Samuel[15]. He carried out compressive tests of aluminum samples whichare prepared AlCu4 Mg aluminum chips and found that steel rein-forcement substantially increases the hardness of aluminum ma-trix. The increasing ratio of hardness values for 20% AISI 1040steel weight content composite are calculated as more than threetimes approximately.

Compressive tests were applied to three different composites toinvestigate the effect of 1040 steel weight (%) content on compres-sive strength of composites and obtained measurement results

(b) three point bending test fixture oint bending test xtures.

(b) 70%Al30%AISI1040

AISI1040

ure of composite specimens.

Fig. 6. Density of the samples before and after sintering.

60

70

15 20 25 30 35 40 45AISI 1040 Steel Content (wt %)

Com

pres

sive

Elo

ngat

ion,

(%

Fig. 9. Compressive elongation & steel content graph of composite materials.

R. Guluzade et al. /Materials andgive in Fig 8. According to test results, the increasing of steelweight (%) contents were enhanced the strength of composites.As it could be seen in Fig. 8, compressive strength of the specimenwith 40% of steel reinforcement is highest in 650 C sintering tem-

Fig. 7. The graph showing the relation between hardness and steel chips content.peratures. This situation could be associated with the highest den-sity of this specimen among the others. When steel chipreinforcement increases in composites, the distance between themdecreases. Therefore movement of dislocations is harder because ofthe existence of more barriers and then, dislocation pile up occurs.This phenomena brings to an end the decreasing in elongation andare presented in Fig. 9 [9]. When compared compressive test re-sults of aluminum according to literature [15], the increase of steelweight (%) content provides the positive effect on compressivestrength for reinforcement of steel. The ability of the combinationand bonding of between steel reinforcement and aluminum com-posites were investigated on SEMs (Figs. 1012). In addition, EDS

550

600

650

15 20 25 30 35 40 45AISI 1040 Steel Content (wt %)

Com

pres

sive

Stre

ngth

, MPa

Fig. 8. Compressive strength and 1040 steel weight contents (%) graph.80

)

Design 52 (2013) 345352 349analysis of composites in term of steel contents is given inTables 49.

According to AlFe phase diagram given in Fig. 13 [16], we cansee that Al3Fe (Fcc) can be occur about 650 C of sintering temper-ature [16]. When in Tables 49, are investigated in terms of Feweight (%) and Al weight (%), we obtain that Al weight (%) content

Fig. 10. Morphology of sintered surface of 20% AISI 1040 steel chip weight (%)content of composite.


and350 R. Guluzade et al. /Materialsdecreases by increasing steel weight (%) content in region A. How-ever, Fe weight (%) in region B increases by increasing steel weight(%) content. It can comment that a simple role exchanged between


Table 5EDS analysis results for region B of 20% AISI 1040 steel reinforced composites.

Element Wt.(%) Atomic (%)

Al 96.6 93.73Mn 0.65 1.19Cu 0.82 1.02Si 0.78 0.84Mg 0.32 1.35Fe 0.85 1.87Total 100 100




Table 4EDS analysis results for region A of 20% AISI 1040 steel reinforced composites.


Fe 96.35 90.1C 2.15 7.01Mn 0.29 0.55Al 1.21 2.34Total 100 100

Table 6EDS analysis results for region A of 30% AISI 1040 steel reinforced composites.


Fe 97.81 92.24C 1.45 6.34Mn 0.32 0.6Al 0.42 0.82Total 100 100Table 8EDS analysis results for region A of 40% AISI 1040 steel reinforced composites.

Design 52 (2013) 345352Al and Fe occurs originating AlFe dispersion. In other words, Alatoms may diffuse into the into the Fe crystal particles and may re-act this phase [17,18].

As the combination of Al and steel chip is investigated fromSEM, their borders exhibit continuity. We can imply that the


Fe 98.16 93.6C 1.13 5.02Mn 0.34 0.65Al 0.37 0.73Total 100 100

0

2

4

6

8

10

12

14

16

18

20

0.01 0.02 0.03

20 %30 %40 %

Strain (%)

Stre

ss, M

Pa

Fig. 14. Flextural strengths of composites according to AISI 1040 steel chip weight(%).

Fig. 13. AlFe phase diagram computed for the AlAl3Fe equilibrium.




sintering process which based on sintering time, temperature andsintering tube application is convenient. However, some voids andporosities were seen on some chip borders. It can be commentedthat they stem from oxidation during the sintering process. Whilethe steel contents are increased, the composites become denser(Fig. 6) as well as inexible so that the elongations of compositesare shorter [19].

Three-point bending tests were carried out on composite spec-imens to ascertain the exural strength and fracture toughness.Fig. 9 shows the effect of various amounts of AISI 1040 steel chipreinforcement on the exural strength of composites. It was ob-served that exural strength and fracture toughness values de-creased as the AISI 1040 steel content increased (Fig. 14). Forexample, 20% AISI 1040 steel weight content composite had a ex-ural strength of 16.05 MPa whereas 40% AISI 1040 steel contenthad a exural strength of 14.17 MPa.

ets. The ductility of the fracture surface can be seen by decreasingsteel weight contents of composites [20,21]. The brittle fracturesurfaces were observed in 30% and 40% AISI 1040 steel chip rein-forced Al composites (Figs. 17 and 18), because the fracture surface

Fig. 16. Fracture surface of 20% AISI 1040 steel chip weight (%) content ofcomposite.



R. Guluzade et al. /Materials andThe relation between fracture toughness and steel content is gi-ven in Fig. 15. The same phenomenon of exural strength was ob-served in the fracture toughness of composites. 20% AISI 1040composites were exhibited the fracture toughness values and40% steel weight content composite showed poor fracture tough-ness values for all notches as well as increasing notch depths.Moreover, the increase of volume percent of steel content reducesthe fracture toughness of a metal matrix composite because it re-sults in the formation and combining of voids within the matrixthat can cause premature fracture. This is due to the increase inconstraint on matrix deformation and consequent reduction inductility. In this case, porosity is the discontinuity. This leads tofailure of the composite.

According to the initial notch depths (a/W), the fracture tough-ness shows different values. The fracture toughness shows littlechange versus the increasing notch depth [13]. Additionally, whencomposite materials are investigated in terms of steel contents, thehighest fracture toughness values are seen on 20% AISI steel weightcontent composites as shown in Fig. 15. In order to realize, thedamage mechanism responsible for the toughening of compositesas a result of AISI 1040 steel weight contents, the morphologiesof fracture surfaces were examined by SEM images.

SEMs of fracture surfaces of the three point exural testsaccording to changing steel weight contents are shown in Figs. 1618. Examination of fracture surface by SEM given in Fig. 16 revealsthat the ductile fracture is predominant. The increasing steelweight content affects the ductility of fracture surface. The differ-ences between amounts of ductility according to steel weight con-tents are clearly evident in the micrographs. Ductility is generallydemonstrated in the form of micro-void coalescence in the fracturesurface, whereas a brittle fracture will have more angular, at fac-

0.02

0.03

0.04

0.05

0.080 0.085 0.090 0.095 0.100 0.105

20 %30 %40 %

K IC

(N/m

m3/

2 )Initial Notch Depths (a/W)

Fig. 15. Fracture toughness vs. initial notch depths.Design 52 (2013) 345352 351of composites contains more angular and at facets. Fracturesurfaces of 20% AISI 1040 reinforced Al composites revealed dimplepatterns showing ductile behavior.

4. Conclusions

On the basis of presenting the investigation of manufacturingrecycled composites from granulated AlMg1SiCu aluminum andAISI 1040 chips it has been concluded that

When steel chip content increased in composites, the hardnessof specimens increased to a maximum value of 121 BHN.

High temperatures under melting point for aluminum causes adecrease in the porosities of specimens and high temperaturescause better bonding between aluminum and steel chip, thusthis improves the mechanical properties of composites. There-fore determined 650 C sintering temperature increased the sin-tered density and mechanical properties.

Compressive strength enhanced with increasing steel chipweight (%) contents. The maximum compressive strength isapproximately 640 MPa which contains 40 weight (%) contentsteel chip.

According to the three-point bending tests, the fracture tough-ness of composites changed little with increasing notch depths.In terms of AISI 1040 steel weight (%) contents, 20% steel rein-

[3] Gronostajski J, Kaczmar JW, Marciniak H, Matuszak A. Direct recycling ofaluminium chip into extruded products. J Mater Process Technol1997;64:14956.

[4] Gronostajski JZ, Marciniak H, Matuszak A, Samuel M. Aluminiumferrochromium produced by recycling of chip. J Mater Process Technol2001;119:2516.

[5] Gronostajski J, Matuszak A. The recycling of metals by plastic deformation: anexample of recycling of aluminium and its alloys chip. J Mater Process Technol1999;92:3541.

[6] Gronostajski J, Marciniak H, Matuszak A. New methods of aluminium-alloychip recycling. J Mater Proces Technol 2000;106:349.

[7] Chmura W, Gronostajski Z. Bearing composites made from aluminium andaluminium bronze chip. J Mater Proces Technol 2006;178:18893.

[8] Abdizadeh H, Ashuri M, Moghadam PT, Nouribahadory A, Baharvandi HR.Improvement in physical and mechanical properties of aluminium/zirconcomposites fabricated by powder metallurgy method. Mater Des2007;32:441723.

[9] Zhao B, Zhu C, Ma X, Zhao W, Tang H, Cai S, et al. High strength Ni basedcomposite reinforced by solid solution W(Al) obtained by powder metallurgy.Mater Sci Eng A 2007;456:33743.

[10] McKie A, Winzer J, Sigalas I, Hermann M, Weiler L, Rdel J, et al. Mechanicalproperties of CBNAl composite materials. Ceram Int 2011;37:18.

[11] Showaiter N, Yousef M. Compaction, sintering and mechanical properties ofelemental 6061 Al powder with and without sintering aids. Mater Des2008;29:75262.

[12] Fogagnolo JB, Ruiz-Navas EM, Simon MA, Martinez MA. J Mater ProcessTechnol 2003;143144:7925.

[13] Arikan H, Sahar F. Fracture and mechanical properties of steel bre Zn5Al(Zamak 5) alloy. Int J Mater Sci 2010;23:1735.

[14] Wang C-J, Huang C-Y. Effect of TiO2 addition on the sintering behavior

352 R. Guluzade et al. /Materials and Design 52 (2013) 345352forced composites have the highest fracture toughness values.

Moreover, we know that the steel reinforcement increases thecompressive strength. However, to improve mechanical propertiesand decrease the porosity of composites, the cold pressing pressurecan be increased and the different sintering temperatures can beused to investigate the effects of sintering temperatures for den-sity, porosity and mechanical behaviors.

Acknowledgement

The present research was conducted as part of the Scientic Re-search Project funded by the Selcuk University in Turkey.

References

[1] Gronostajski JZ, Kaczmar JW, Marciniak H, Matuszak A. Production ofcomposites from Al and AlMg2 alloy chip. J Mater Process Technol1998;77:3741.

[2] Gronostajski J, Chmura W, Gronostajski Z. Bearing materials obtained byrecycling of aluminium and aluminium bronze chip. J Mater Process Technol2002;125:48390.hardness and fracture toughness of an ultrane alumina. Mater Sci Eng, A2008;492:30610.

[15] Samuel M. A new techniques for recycling aluminium scrap. J Mater ProcessTechnol 2003;135:11724.

[16] Alravc CA, Pekgleryz MO. Calculation of phase diagrams for the metastableAlFe phases forming in direct-chill cast aluminium alloy ingots. Calphad1998;22(2):14755.

[17] Tang F, Anderson IE, Gnaupel-Herold T, Prask H. Pure Al matrix compositesproduced by vacuum hot pressing: tensile properties and strengtheningmechanisms. Mater Sci Eng, A 2004;383:36273.

[18] Bayraktar E, Katundi D. Development of a new aluminium matrix compositesreinforced with iron oxide (Fe3O4). J Achievements Mater Manuf Eng2010;38:714.

[19] Baron RP, Wert J, Gerard A, Wawner FE. The processing and characterization ofsintered metal-reinforced aluminium matrix composites. J Mater Sci1997;32:643545.

[20] Mann RED, Hexemer Jr, Donaldson IW, Bishop DP. Hot deformation an AlCuMg powder metallurgy alloy. Mater Sci Eng, A 2011;528:547683.

[21] Mashhadi HA, Moloodi A, Golestanipour M, Karimi EZV. Recycling ofaluminium alloy turning scrap via cold pressing and melting with salt ux. JMater Process Technol 2009;209:313842.

Fracture toughness of recycled AISI 1040 steel chip reinforced AlMg1SiCu aluminum chip composites1 Introduction2 Experimental details2.1 Raw materials2.2 Compaction and sintering

3 Results and discussion4 ConclusionsAcknowledgementReferences

Documents

Fracture Toughness of Recycled AISI 1040 Steel Chip Reinforced