The Microstructure and Wear Resistance of a Copper Matrix Composite Layer on Copper via Nitrogen-Shielded Arc Cladding
A TiN and TiN·Ti2Cu reinforced copper matrix composite layer was cladded onto a T3 copper substrate to improve the anti-wear performance of copper products by means of the nitrogen-shielded gas tungsten arc cladding method (N2-GTAC). Better than the traditional preparation method of TiN, the TiN particles in the cladding layer were in situ generated using N atoms of shielding gas and Ti atoms of pre-deposited metal powders. In addition, the composite phase TiN·Ti2Cu occurred in the cladding layer, which also had a positive effect on anti-wearing. As Ti increased, the amount and grain size of TiN·Ti2Cu and TiN increased as a result. The hardness of the cladding layer increased with the increasing amount of reinforced phase generated in the layer. The hardness of the layer reached a maximum of 410 HV, which is nearly 5.1 times greater than that of copper. The TiN·Ti2Cu- and TiN-reinforced phases improved the wear resistance of the cladding layers. The cladding layer with 15 wt % Ti had the longsest launch stage (600 s) and the lowest fiction coefficient (0.56).
Directly Writing Patterning of Conductive Material by High Voltage Induced Weak Electric Arc Machining (HV-μEAM)
An additive manufacturing (AM) method for the deposition of metallic layer in micron scale on monocrystalline silicon wafer surface by high voltage induced weak electric arc machining (HV-μEAM) has been proposed. The process characteristics of HV-μEAM are analyzed to fulfil the metal material deposition. The influence of the processing parameters on the deposition effect were studied with copper as additive electrode material. Using the optimal parameters, a number of complex trajectory deposition experiments have been carried out and a QD character-type deposition layer with a height of 139.09 μm has been obtained. The deposition has good continuity and high forming precision. It is proven that the new method is achievable and efficient for patterning metallic materials in the micro- and nano-scale on the silicon substrates surface.
Wear and oxidation properties of titanium aluminides formed on titanium surface by laser alloying
Abstract Titanium aluminides were formed on a commercial purity Ti substrate by laser alloying using a preplaced Al powder bed. The resistance to wear and oxidation was evaluated for the alloyed layers. Alloyed layers with penetration ratios ranging from approximately 20% to 60% were obtained by controlling the laser power and traverse speed. The phases formed in the alloyed layers were changed in the following ways as the penetration ratio increased: Al + TiAl 3 →( Al )+ TiAl 3 →( TiAl 3 )+ TiAl →( Ti 3 Al a Ti 3 Al where the phase within the parentheses is the minor phase. The alloyed layers had a higher adhesive wear resistance than that of the commercial purity Ti. The alloyed layers predominantly of Ti3Al had superior wear resistances because of their high hardnesses. The alloyed layers had significantly higher oxidation resistances at 1273 K in dry air flow than that of the commercial purity Ti. Of the alloyed layers, the (TiAl3)+TiAl layer had the best oxidation resistance.