Development and Characterization of Functionally Gradient Al Si Alloy Using Cast-Decant-Cast Process

Transcription

1 DOI /s TECHNICAL PAPER Development and Characterization of Functionally Gradient Al Si Alloy Using Cast-Decant-Cast Process B. Anandavel S. S. Mohamed Nazirudeen J. Anburaj P. C. Angelo Received: 29 November 2014 / Accepted: 25 February 2015 / Published online: 2 June 2015 The Indian Institute of Metals - IIM 2015 Abstract A cylindrical component of functionally gradient Al alloy with high silicon in the outer and low silicon in the core was produced using cast-decant-cast (CDC) process. The preparation of the component consisted of pouring high Si Al alloy first into a cylindrical mould, decantation of un-solidified liquid after the alloy solidified for a desired thickness against the mould walls and subsequently pouring the low Si Al alloy at superheated temperature, so that the first alloy got partially re-melted forming a functionally gradient material (FGM) region between the two. The characteristics of FGM region like depth, size, shape and distribution of Si particles in the cross section of CDC alloy were evaluated by optical microscopy. Hardness tests and sliding pin-on-disc wear tests were carried out to compare hardness and wear resistance of outer, FGM and core regions. The micrographs of wear surfaces showed that the FGM region has better wear resistance as compared to outer and core regions as seen from the decreased delamination of wear tracks. Keywords Cast-decant-cast FGM layer Hardness Wear resistance B. Anandavel (&) Research Scholar, Department of Metallurgical Engineering, Government College of Engineering, Salem , India anandavel1977@yahoo.co.in S. S. Mohamed Nazirudeen J. Anburaj P. C. Angelo Department of Metallurgical Engineering, PSG College of Technology, Coimbatore , India 1 Introduction Quest for materials with superior wear resistance under the sliding condition along with better mechanical properties has gained momentum in recent years. One of the potential materials satisfying the above requirement is functionally gradient material (FGM). In comparison with a traditional alloy, FGM alloys have a gradual change in composition and microstructure across their cross section, resulting in enhancement of mechanical properties for high friction applications [1, 2]. Common techniques used to produce functionally gradient metallic materials are, arc welding processes, laser melting, thin film coatings, powder metallurgy, hot spraying, thermal barrier coatings, etc., [3, 4]. Recently, Al Si alloys, Al Si SiC composite materials, Al Si Mg alloys, etc., are being studied for fabrication of FGM alloys by melting route because of their excellent casting and wear properties [5]. Past research has shown that light alloys with transition in concentration of Si, SiC, Al 2 O 3 particles have been produced effectively by casting techniques [6, 7]. Tomid et al. [5] fabricated primary particle reinforced surface FGM composites using laser surfacing method. Yaan [8] produced hyper eutectic Al Si FGM composite by remelting and fast cooling method. Many of these techniques using existing processing techniques are expensive due to initial investment required or high cost of the metallic materials [8, 9]. Put and Vleugels [4] reported in situ primary Si particle reinforced Al based FGM composites by centrifugal casting method. In the FGM alloy, introduction of second particles as reinforcement has been a big challenge [10, 11]. The centrifugal casting process is limited to basic shapes such as cylinder and symmetrical components. Scanlan et al. [12] described a very simple process by which the light metal FGM composites can be easily

2 S138 Trans Indian Inst Met (2015) 68(Suppl 2):S137 S145 produced by pour-over method and this process was termed as cast-decant-cast process (CDC). According to them, three methods known as turnover, internal decant and low pressure methods are associated with CDC process to produce FGM alloys [12]. Using CDC process, Al Si alloys with reinforced SiC particles and Al Si Mg alloys with precipitates can be produced to any shape according to specific requirement [13 15]. Silicon is present as fine particles uniformly distributed in the structure increasing the strength. However, when the primary Si particles are coarse with polyhedral shapes, the strength decreases with increasing Si content, while hardness increases due to increased number of Si particles [16]. Chen and Alpas [17] investigated wear mechanism in eutectic Al Si alloys tested against a hardened steel counter-face and explained the delamination mechanism for the dry wear with respect to microstructure and hardness. However, for fabrication of FGM alloys by CDC process, a detailed study on the process and characterization of Al Si alloys with different concentration of Si particles in the CDC alloy has not yet been established. The purpose of this paper is to produce bulk FGM Al Si alloy with high Si in the outer layer and with low Si in the inner layer using CDC process. Microstructure, hardness and wear resistance of outer, FGM and core regions in the CDC alloy are reported. 2 Materials and Methods 2.1 Preparation of FGM Alloy A cylindrical component of cast Al Si alloy with high Si concentration (Alloy A) in the outer region and low silicon concentration (Alloy B) in the core was produced by CDC process. The chemical compositions of the two aluminium alloys, such as Alloy A and Alloy B, used for the present work are given in Table 1. The schematic diagram of the locally fabricated CDC equipment is shown in Fig. 1. This equipment consists of a cylindrical metallic mould of 50 mm diameter and 100 mm length made of 316L austenitic stainless steel. With metallic mould, a copper coil cooling system is attached to facilitate the rapid solidification of the molten metal. A hydraulic pumping system is also provided for the mould Fig. 1 Schematic diagram of indegeneously fabricated CDC equipment for ejecting the casting as well as for inverting the mould. The aluminium alloys selected for outer and inner layers in CDC alloy were melted separately at 750 C in an inconel crucible by electrical resistance melting furnace. The steps involved in the CDC process consist of pouring the Al-alloy with high silicon content of 13.5 wt% (Alloy A), as an outer layer for good wear resistance, into a metallic mould and allowed to partially solidify for a predetermined time against the metallic mould for a desired thickness. When the desired thickness of high Si alloy was formed in the mould, the remaining unsolidified liquid metal was decanted and the other Al liquid metal with low 5.5 wt% Si (Alloy B) at sufficient superheated temperature, i.e. about C above the melting of the alloy B, as a core for good load bearing capacity, was poured into the mould. While the low Si liquid metal was poured into the mould, the first solidified layer gets partially melted and this causes Si particles to diffuse from the high Si concentration side to low Si concentration side, i.e., from outer region to core in the CDC alloy. This is due to the increased heat flow across the interface of the two alloys. According to Mohammadi Rahvard et al. [16], the rate of diffusion of Si particles from outer surface to core varied with respect to the superheat temperature of the molten Table 1 Chemical composition of alloy A and alloy B Alloys Chemical composition (in wt%) Si Cu Mn Mg Zn Fe Al Outer (alloy A) Balance Core (alloy B) Balance

3 S139 Fig. 2 Successive steps used for preparation of FGM alloy in CDC process metal of the second alloy and thickness of first alloy formed in the metallic mould. A completely solidified Al Si alloys having gradient in Si concentration from outer region to core region can be removed from the metallic mould by an ejecting pin as shown in Fig. 1. The sequence of steps used for preparation of FGM alloys in the present work is shown schematically in Fig. 2. The process steps are: step 1 the mould with upright position for pouring the Alloy A (i.e., high Si) into the mould; step 2 the mould with inverted position for decantation of unsolidified high Si metal; step 3 the mould is returned back to its upright position containing high Si layer next to its mould walls; step 4 the mould is kept in upright position and the alloy B with low Si is poured and step 5 CDC alloy ejected after complete solidification. The CDC casting was photographed using a digital camera so as to distinguish the outer and core layers and the macrograph of the Al Si FGM alloy showing two different layers, as outer and core, is given in Fig Microstructural Analysis The microstructural characterization was carried out for the FGM Al-alloy produced through CDC process to identify the FGM region in cross section using an optical microscope. Samples for optical microscopy were prepared by standard metallographic techniques and etched for s in Keller s reagent (190 ml distilled water, 5 ml HCl, 3 ml HNO 3, 2 ml HF) and washed with forced water. Volume fractions and size of primary and eutectic silicon particles present in the Al-matrix were quantified at different regions of the cross section of the CDC alloy using image analyzer software (Metal plus). Fig. 3 Macrograph of CDC casting showing high Si and low Si regions 2.3 Hardness Testing Hardness survey was carried out for CDC alloy in the cross sectional area with an interval of 5 mm distance from the outer surface to the core region to evaluate the width of the outer region with high Si, FGM region with Si gradient and core region using a Mitutyo micro-hardness tester by employing a load of 50 g for 15 s. The reported values are average of five readings. 2.4 Wear Testing The standard samples with 8 mm in diameter and 25 mm in length for wear tests (confirming to ASTM G 99) were prepared from the region of outer layer, FGM layer and

4 S140 core of the CDC Al alloy casting. The wear behavior of high Si region, FGM region and low Si region in the CDC Al-alloy was investigated using a dry sliding pin-on- disc type wear testing machine. Wear tests were conducted against hardened steel disc of 40 mm in diameter, 850 VH in hardness and 0.11 lm in surface roughness. The wear test samples were mounted in the sample holder and kept perpendicular to the rotating disc. The parameters used in wear tests were as follows: the rotation speed of the disc (N) was 1000 rpm, the applied load was 50 N, the diameter of the wear track was fixed as 100 mm and the test time was varied between 1 and 5 min. Using these parameters, the sliding distance for each run was calculated by Eq. (1) given below [18] L=pDNT=60 ðmþ ð1þ where L is the sliding distance (m), D is the diameter of the wear track (mm); N is the speed of rotation of the disc (rpm); T is the test time (minutes). The standard wear procedures were followed for evaluating the resultant wear volume (mm 3 ) and wear rate (mm 3 /m) for each condition as a function of sliding distance. The wear volume and wear rate of the tested samples were calculated from the testing parameters used by the following two equations [5]: Wear volume; mm 3 ¼ ðmass loss; gþ 1000 ðdensity, g cm 3 Þ Wear rate; mm 3 m ¼ Dm=qL ð2þ ð3þ where Dm is the mass loss (g); q is the density (g/cm 3); Lis the sliding distance (km). The disc surface was cleaned with acetone before each experiment. All the tests were carried out in dry sliding condition and at room temperature. The wear test samples (i.e., pins) were weighed both before and after the testing using a high precision electronic balance. After the test, wear tracks were examined by SEM (model: JEOL JSM6360) to study the wear characteristics. Trans Indian Inst Met (2015) 68(Suppl 2):S137 S145 3 Results and Discussion 3.1 Optical Microstructural Analysis Optical micrographs of CDC Al-alloy s outer layer, FGM layer and core are shown in Fig. 4. The micrograph of outer region, Fig. 4a, shows fine equiaxed grains with a uniform distribution of Si particles in the a-al eutectic matrix. Partially modified Si particles within eutectic Almatrix were observed in the microstructure. The presence of Si particles decreased with distance across the cross section in the CDC alloy, as seen from the micrograph (Fig. 4a). The average size of Al grains observed in the outer layer of the CDC Al alloy was about lm and very much finer when compared to FGM and core regions. This is due to faster cooling rates during solidification in the metallic mould provided with cooling system. Figure 4b shows the optical microstructure of FGM region. This layer is formed in CDC alloy by partial melting of the layer of alloy A (high Si). This results in diffusion of Si particles at the interface between high Si concentration to low Si concentration inward to the core region. Figure 4b shows equiaxed Al grains with a uniform distribution of Si particles in the Al matrix. The average size of Al grains is about lm and is slightly coarser than that of outer layer. A unique observation found in the FGM microstructure is that of a perfect and good metallic interface without a separate domain of Al matrix. The average size of Si particle observed in the FGM region is about 10 lm in diameter and lm in length. The FGM microstructure shows that the Si particles are decreasing gradually with distance from the outer layer, as seen in Fig. 4b. The mixed shapes of needle and round Si particles were found in the FGM region and this mixed shapes of Si particles gives interesting characteristics of hard and tough regions in the FGM [16]. Optical microstructure of core region in CDC Al-alloy (Fig. 4c) shows coarse dendritic a-al grains, about 40 to 50 lm in diameter and eutectic Si particles at the grain Fig. 4 Optical micrographs of CDC Al-alloy at a Outer, b FGM and c core regions

5 boundaries. Si particles in the microstructure are of needle shape with size varying from 20 to 25 lm in length. The coarse grains and needle shape Si particles are attributed to the slow cooling rates of the Al-alloy in the core region during solidification [19]. It is found from the microstructure that the shape of Si particles varied depending on the thermal condition of the alloy B (low Si). In this study, round shape Si particles were observed in the outer most region, the mixed shapes of round and flaky Si particles of varying size in the FGM and needle like Si particles in the core region. It is possible to produce cylindrical solid component in Al alloy with graded Si concentration using a simple and economically viable cast-decant-cast (CDC) process. Compared to the width of the FGM zone in a centrifugal casting, the CDC casting shows wider transition zone. This is due to remelting of the alloy A which solidified against the mould wall and due to the super heat temperature of the alloy B poured into the mould along with high Si layer. This observation is in good agreement with the findings of Scanlan et al. [12] who carried out experimental study on casting an Al Si alloy using the turnover technique. Results of the volume fraction of Si particles estimated in the CDC Al alloy with distance from the edge of the casting are given in Fig. 5. It is observed that the volume fraction of Si particles decreases with increasing distance from the outer surface. However, the size of Al grains was found to increase with distance from the outer surface across the cross section of the CDC alloys. This is due to change in the solidification pattern of the two alloys. The width of the alloy A solidified in the mould and the liquid temperature of the alloy B poured into the mould resulted S141 in the formation of a-al grains and Si particles in CDC alloy. When pouring the alloy B liquid metal at maximum superheated temperature into the mould, the remelting of the solidified layer of alloy A causes the redistribution of Si particles across the cross section of the casting by diffusion from Si rich region (i.e., alloy A) to Si lean region (i.e., alloy B) through the interface between outer and core regions. According to Mohammadi Rahvard et al. [16], the solidified layer of alloy A against the mould wall can directly influence the thermal conduction to the alloy B liquid metal, leading to change in the microstructure and width of the transition zone between the two alloys. From the hardness values reported, the width of FGM region formed in the CDC alloy is about mm in thickness which is much higher compared to the thickness of FGM region produced by other techniques [12]. With graded Si particles in the a-al matrix, it is found that the two alloys mixed with each other and formed an interface without any demarcation across the cross section of the casting as shown in Fig. 4. It is interesting to note that the size of Al grains was found to increase with decrease in Si particles from outer region to core region in the CDC alloy. This is due to less number of nucleation sites (lower Si particles) and slow rates of conduction of heat for the alloy B liquid to cool during solidification [16]. The higher solidification rate and higher volume of Si particles at the interface results in refinement of the grain size in the FGM region [20]. Another unique observation found on the distribution of Si particles in the FGM region is that no agglomeration or porosity was noted through out the cross section of the CDC alloy. Earlier investigations on Al Si alloys produced by centrifugal casting and other techniques Fig. 5 Volume fraction of Si particles with distance from edge of the casting

6 S142 reported a lot of porosity along with agglomeration of second particles in the matrix [13 15]. 3.2 Microhardness Testing Hardness survey carried out for the CDC alloy from outer surface to core is shown in Fig. 6. It shows that hardness variation from outer surface (94 VHN) to the core (60 VHN) corresponding to the change in Si concentration in the CDC alloy. As is evident, the outer layer shows higher hardness with consistent hardness values due to the presence of constant amount of Si content. While in the FGM region, the hardness progressively decreased with distance from the outer surface. This is due to gradual change in concentration of Si particles and presence of coarse grained structure. It is observed that the transition zone at the interface exhibits a gradual change in hardness indicating the continuous change in the matrix with graded Si particles. At core region, lower hardness was observed when compared to outer and FGM regions. This is attributed to the presence of less Si particles and the formation of coarse grains in the Al-matrix. This is in confirmation of the microstructural characteristics of the CDC alloy in the different zones. This is in good agreement with results of previous work [19] which reported that the change in Si concentration proves to be an excellent way of achieving interesting mechanical properties, however at the expense of ductility and corrosion resistance. Culliton et al. [21] reported that a good interface between the Si particles and Al matrix always gives rise to higher hardness. Incorporation of about 20 % Si particles in Al matrix shows the highest hardness values. 3.3 Wear Testing Trans Indian Inst Met (2015) 68(Suppl 2):S137 S145 The results of wear tests for CDC alloy at the outer region, FGM region and core region show that the wear resistance of outer region is markedly increased compared to core region, while it is almost equal with FGM regions under the same condition. In fact, at higher sliding distance, wear resistance of FGM region was found to be better than in the outer region as seen from curves in Figs. 7 and 8. Figure 7 shows the volume of wear (mm 3 ) for the different regions in CDC Al alloy as a function of sliding distance. It can be seen from Fig. 7 that higher volume of wear ( mm 3 ) was observed in the core region as compared to FGM and outer regions. This is due to the presence of coarse Al grains with very low amount of Si particles in the core region. In contrast, the wear volume for FGM region was almost equal to that of the outer layer at sliding distance of 20 km and both outer and FGM regions show identical wear trend in dry sliding pin-on-disc wear test. This is due to the microstructural characteristics of FGM regions having fine grains with mixed shapes of Si particles. The wear volume of Al Si alloy mainly depends upon the interfacial strength and distribution of Si particles in the eutectic Al matrix. The wear results confirm the microstructural and hardness of different regions formed in CDC Al alloy. This result is in good agreement with the findings of a number of previous workers [22, 23] who have reported that the Al Si alloys with gradient in Si concentration exhibit considerably higher wear resistance as compared to Al Si alloy with no gradient. The plot of wear rate for different regions formed in the CDC Al alloy as a function of sliding distance is shown in Fig. 8. It is interesting to note that the wear rate increases Fig. 6 Microhardness of CDC alloy with distance from outer surface to core Fig. 7 Wear volume in the three regions as a function of sliding distance

7 S143 Fig. 8 Variation of wear rate for the three regions as a function of sliding distance with the increase in sliding distance for all the regions in the CDC Al alloy. However, the degree of wear resistance of these three regions was clearly differentiated by calculated wear rate with sliding distance in wear test. The wear rate of FGM is almost the same that of outer region. This is due to the modification of the shape of Si particles from round to flaky and redistribution of particles in the interface of the two Al Si alloys. The remelting of the first alloy due to pouring of second alloy with higher superheat brings out uniform distribution of Si particles along with fine Al grains through diffusion controlled mechanism in the interface layer [24]. Hence it has been found that the fine a- Al grains with slightly flaky Si particles are more effective for sustaining the increased load. The minimum variation of wear rate on the FGM region in the CDC Al alloy for the entire range of sliding distance investigated suggests that the diffused Si particles with modified shape in the FGM region act as better load bearing agents than the Si particles present in the outer and core regions. The coarse Si particles have a tendency to crack and accelerate the wear rates [25]. Thus it may be stated that wear rates is an indirect measure of the load bearing capacity of the FGM region, which highlights the importance of the gradual decrease in concentration of Si particles in reducing the wear rate of the FGM region. The wear properties of Al Si alloys mainly depend upon the microstructure, in particular, size and distribution of Si particles in the a-al eutectic matrix [26, 27]. Many previous workers [2, 20, 21] have reported that Al alloy with high Si content provides very good wear resistance, while Si content of about 14 to 16 wt% provides the optimum wear resistance. The presence of large Si particles in the Al Si alloys has been recognized as the main limitation for their industrial use, because the coarse Si particles tend to rise brittleness and easy to cracking the soft Al matrix resulting in catastrophic failures during service [28, 29]. Wear resistance of outer layer and FGM layer of the CDC alloy was found higher when compared to the inner layer of the CDC alloy. The improvement of wear resistance of these two layers is attributed to the presence of fine grain size of a-al, besides the refinement of Si particles. As is evident from the optical microstructures, fine grains were noted for FGM and outer layers of CDC alloy (Fig. 4a, b). This is due to the influence of thermal conduction during solidification. The outer layer was poured against mold walls, which extracted heat much faster as compared to the extraction of heat by inner layer. As a result, outer layer shows modified Si particles with very fine a-al grains. In the present paper, the effect of plastic deformation on wear behavior of CDC alloys was not studied. However, the influence of plastic deformation on wear resistance of outer and FGM layers will be taken up for future work. 3.4 SEM Analysis The wear testing results can be further examined by detailed analysis of the wear surfaces of the tested CDC Al alloy samples. The SEM micrographs of wear surfaces of outer region, FGM region and core region at low and high magnifications are shown in Figs. 9 and 10 respectively. It is, in general, observed that a combination of adhesive and abrasive wear was noted for the CDC alloy. The low magnification SEM micrographs, Fig. 8, reveal fine scoring along the wear direction. The depth of scoring is higher for core when compared to outer and FGM regions. This indicates that the highest wear rate was observed for inner layer and the lowest wear rate for FGM region, as seen from SEM micrographs (Fig. 9). The presence of deep scoring marks in the core region is due to abrasion by entrapped debris and hard asperities on the hardened steel counter face [26]. The SEM micrographs of the wear surfaces at higher magnification reveal the fact that the severe plastic flow and cracking was observed in the tested samples during sliding. Also it is possible that hard particles or fractured species mechanically got dislodged during wear test. Deuis et al. [22] made a detailed analysis of dry sliding wear of Al Si alloys. They found that particle delamination is one of the important mechanisms controlling the wear of particle reinforced aluminium composites. The important factors affecting wear performance of the Al Si alloys are (i) the second phase particle size, (ii) inter-particle spacing and particle or matrix interfacial bonding. Birol and Birol [27] reported that during delamination wear, crack nucleation was favored by the second phase particles and its distribution. Saka et al. [14] demonstrated that the

8 S144 Trans Indian Inst Met (2015) 68(Suppl 2):S137 S145 Fig. 9 SEM micrographs of wear surfaces at lower magnification for a outer region, b FGM region and c core region in the CDC alloy (Load 50 N, speed 1000 rpm and sliding distance 25 km) Fig. 10 SEM micrographs of wear surfaces at higher magnification for a outer region, b FGM region and c core region in the CDC alloy (Load 50 N, speed 1000 rpm and sliding distance 25 km) delamination wear is the principal mechanism during dry sliding wear of FGM alloys. It may be noted that the CDC process can also be extended for development of components containing multi layered structures with different properties in the core and outer layers. 4 Conclusions 1. Using CDC process, a wide width of gradual gradient in the concentration of Si particles at the interface between high Si and low Si Al alloys could be developed. It was also observed that the FGM region shows a perfect metallic bonding with other regions. 2. The amount of Si particles decreases gradually with distance from the outer surface to core region. The fine and uniform distribution of Si particles in the Al matrix was observed for FGM region. 3. The hardness is found to continuously decrease with distance from 94 VHN in the outer region to 60 VHN in the core region. The variation of hardness across the cross section of the CDC Al alloy corresponds to change in Si concentration. 4. Wear volume and wear rate of FGM region were found to be similar with the outer region and lower than those of the core region. This is due to the presence of fine and uniform distribution of Si particles with average size of 10 lm in diameter in the FGM region. Acknowledgments The authors are grateful to the Defence Research and Development Organization (DRDO) for funding through the R&D project on Development of functionally gradient Al Si alloy using cast-decant-cast process. The authors are very grateful to Mr. A. Chandrasekar and Mr. P. M. Silambaran for experimental support. References 1. Pei Y T, Th J, and De Hosson M, Acta Mater 48 (2000) Prasada Rao A K, Das K, Murty B S, and Chakraborty A, Wear 257 (2004) Watanabe Y, and Fukui Y, Mater Metall Sci 4 (2000) Put S, and Vleugels J, Mater Sci Eng A 390 (2003) Tomid S, Nakata K, and Shibata S, Surface Coat Technol 160 (2003) Mandal A, Murty B S, and Chakraborty M, Mater Sci Eng A 506 (2009) Bakshi S R, Wang D, Price T, Zhang D, Keshri A K, Chen Y, Shipway P H, and Agarwal A, Surface Coat Technol 204 (2009) Yin-Yaan T, J Nonferr Metals 12 (2002) Deshmukh R A, Sundarajan T, Dube R K, and Bhargava S, J Mater process Technol 84 (1998) 56.

9 10. Song C, Xu Z, and Li J, Mater Design 28 (2009) Davies F A, and Eyre T S, Tribol Inter 27 (1994) Scanlan M, Browne D, and Bates A, Mater Sci Eng A 413 (2005) Lee H Y, Jung S H, Lee S K, and Ko K H, Appl Surf Sci 253 (2007) Saka N, Pamies-Teixeira J J, and Suh N P, Wear 44 (1977) Kim J S, Knon Y S, Lomovsky O I, and Dunda O J, Comput Sci Technol 67 (2007) Mohammadi Rahvard M, Tamizifar K, Boutorabi M B, and Gholami S, Trans Nonferr Met Soc China 24 (2014) Chen M, and Alpas T S, Wear 265 (2008) Mittal R, and Singh D, Trans Indian Inst Met 64 (2014) Tripathy M R, Dube R K, and Koria S C, J Mater Process Technol 190 (2007) 342. S Das S, Trans Indian Inst Met 57 (2004) Culliton D, Betts T, Carvalho S, and Kennedy D, J Thermal Spray Technol 22 (2013) Deuis L V, Subramanian C, and Yellup J M, J Mater process Techol 57 (1997) Sundarshan, and Surappa M K, Wear 265 (2008) Novoselvova T, Fox P, Morgan R, and Neill W O, Surface Coat Technol 200 (2006) Singh D, and Dangwal S, J Mater Sci 41 (2006) Chirita G, Soares D, and Silva F S, Mater Des 29 (2008) Birol Y, and Birol F, Wear 265 (2008) Lasa L, and Rodriguez-Ibabe J M, Mater Sci Eng A 363 (2003) Motegi T, Tanabe F, and Sugiura E, Mater Sci Forum 203 (2002) 396.