The infiltration method of preparing W/Cu FGMs can be divided into three kinds of methods:

1.The conventional infiltration method
Stratifying and loading the different preset particle size tungsten powder,then pressing and sintering the tungsten powder,after infiltrating,we can get the different composition ratio W/Cu FGMs.Then corroding the sintered porous tungsten compacts by electrochemical corrosion that can form a gradient porosity changes tungsten compact down by the corrosion direct.Finally, infiltrated the copper,so as to obtain the W/Cu FGMs,which ingredient composition is changing continuously.Because of the different sintering shrinkage rate of conventional infiltration,therefore the distributed ingredient and shape of obtained W/Cu FGMs components can’t be controlled imprecisely.

2.Water-boiled solvent pore forming method
Water-boiled solvent pore forming method is to match the tungsten and copper in accordance with different mass ratio,weighed tungsten powder to mix with the pore forming agent,stacking five layers layer by layer,then pressed it into green compacts in the steel die and placed in a vacuum oven for 2 hours in order to remove organic pore forming agent.Currently,since the widespread use of organic matter to make tungsten skeleton pore forming agent,it will produce  gas after decomposition,making tungsten compacts swelled and ruptured.If the pore distribution is uneven,then there will be copper-rich region and the lean region after copper infiltration. Therefore, it’s necessary to remove the organic pore-forming agent,it will dissolve when boiled,and to obtain a changed porosity gradient,fine and uniform tungsten skeleton,then infiltrating copper quickly,so that you can get the tungsten copper functionally gradient materials with more dense and showed a five-layer gradient structure changes.

3.Infiltration-welding method
Because of the huge different of melting point between tungsten and copper, that makes thetungsten copper functionally graded materials common preparation methods such as tungsten skeleton copper infiltration methods, welding methods,become very difficult to obtain tungsten copper functionally graded materials in a one-time.The researchers found that integrated these two methods can be successfully prepared the good performance of tungsten copper functionally graded materials.This method can be divided into three steps: (1) preparing gradient tungsten skeleton;(2)infiltrating copper;(3)hot welding. It would be strict to the pore forming agent content for using this method to produce tungsten copper functionally graded materials.If exceeds,that will cause severe foaming deformation of tungsten skeleton;if lacks,the porosity of tungsten skeleton can not be guaranteed.

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