a method of fabricating composite articles includes supplying electrical current to an electrically conductive filament . the electrically conductive filament may include a first material that is electrically conductive and a polymer second material . the polymer second material comprises at least one of a thermoplastic polymer and a partially cured thermosetting polymer . the heated filament is deposited according to a predefined pattern in successive layers to adhere the polymer material of the layers together and build up a three dimensional article . the article includes strands of the first material embedded in a substantially continuous polymer matrix of the second material .