Method of three-dimensional printing using a multi-component build powder
Methods are disclosed for making articles ( 2 ) by three-dimensional printing. The methods include three-dimensional printing a build powder mixture which includes a first material powder and a second material powder to form a printed article and subsequently heating the printed article to a temperature at which a sufficient amount of the second material powder melts to enable it to infiltrate throughout the interstices between the first material powder particles so that the article ( 2 ) achieves a room temperature relative density of at least 85 percent of its theoretical density, the theoretical density being the density the article ( 2 ) would have if it contained no porosity. The first material powder has a melting temperature, melting temperature range, or dissociation temperature which is higher than the melting temperature or melting temperature range of the second material powder and the first material powder has no more than a limited amount of solubility in the second material powder.
1. A process for making an article comprising the steps of:
a) providing a build powder mixture comprising a first material powder in an amount of between 50 and 95 volume percent and a second material powder, the first material powder having one selected from the group consisting of a melting temperature, a melting temperature range, and a decomposition temperature, and the second material powder having one selected from the group consisting of a melting temperature and a melting temperature range, wherein the melting temperature or the melting temperature range of the second material powder is less than the melting temperature, the melting temperature range, or the dissociation temperature of the first material powder;
b) three-dimensionally printing the article from the build powder mixture by spreading a layer of the build powder mixture, selectively jet-printing a fluid onto the layer to cause selected portions of the layer to bind together, and repeating the sequence of spreading and selectively jet-printing until the article has been constructed; and
c) heating the printed article to a preselected temperature, the preselected temperature being above the melting temperature or within or above the melting temperature range of the second build powder material and below the melting temperature, the melting temperature range, or the dissociation temperature of the first material powder; and
d) maintaining the printed article at the preselected temperature until the second material powder has infiltrated through the spaces between individual particles of the first material powder so that the article has a relative density at room temperature of at least 85%, wherein:
the amount of dissolution of the first material powder in the second material powder during step (d) is insufficient to reduce the diameter of a particle of the first material powder which had a starting diameter of the mean diameter of the first material powder by more than 25 percent.
2. The process of claim 1 , wherein the first material powder is a metal or a metal alloy.
3. The process of claim 1 , wherein the first material powder is a ceramic.
4. The process of claim 1 , wherein the second material powder is a metal alloy.
5. The process of claim 1 , wherein the first material powder is a stainless steel alloy.