Investigation on WC–Al composite coatings of AZ91 alloy by mechanical alloying

Abstract

In this paper, WC-Al composite coatings of AZ91 alloy prepared by mechanical alloying have been investigated in detail. It was found that the premixing process of composite powders has no significant effect in promoting the formation of uniform coating of WC-Al powders. Under the optimised conditions, i.e. the composition of composite powders of (10 g WC-6?5 g Al-3 g AZ91-0?5 g Mg), ball-to-powder weight ratio of 14 : 1 and milling duration of 12 h, the average thickness of composite coating can be remarkably increased to 38?01 mm. Compared with the bare substrate, the Brinell hardness of the specimen with WC-Al composite coating can be significantly increased by about 90?01%.

Effects of annealing on Al–Si coating synthesised by mechanical alloying

“…The Mechanical alloying (MA) method has been shown to be capable of synthesising alloyed, composite and amorphous coatings on bulk materials with solidstate powders as raw materials [16][17][18][19][20]. The MA method can be applied to synthesise coatings because of its advantages such as the low time and energy consumption, the flexibility of preparing coatings with different structures and the seamless adhesion of the coatings.…”

Nitriding behaviour of Mg-Li alloy with surface mechanical nano-alloying pretreatment

“…With the further collision among present coating, balls and powders, the Ti coating became more thicker and denser. Additionally, owing to the severe plastic deformation, the grain size of Ti coating was gradually refined to nanoscale [12,13,[15][16][17][18][19].…”

“…Recently, a new surface modification method named surface mechanical nano-alloying treatment (SMNAT) has been successfully used to fabricate the nanostructured alloying coatings on metallic materials [10][11][12][13][14][15][16][17][18]. The SMNAT was designed based on the method of surface mechanical attrition treatment (SMAT) and its principle can be summarised as follows: First of all, the sample are placed into the vibration chamber together with the steel balls and alloy powders.…”

“…Second, the collisions among the sample, steel balls and powder particles can be induced by the high-frequency vibration. Thirdly, the powder particles become cold-welded to the sample surface by means of the repeated collisions, resulting to the formation of alloying coating [12][13][14]16,17]. Simultaneously, the grain size of alloy coating and matrix are gradually refined to nanoscale due to the severe plastic deformation [10][11][12][13][14].…”

“…Thirdly, the powder particles become cold-welded to the sample surface by means of the repeated collisions, resulting to the formation of alloying coating [12][13][14]16,17]. Simultaneously, the grain size of alloy coating and matrix are gradually refined to nanoscale due to the severe plastic deformation [10][11][12][13][14]. Ultimately, a nanostructured alloying coating can be formed by this method.…”