This invention relates to a high temperature melting composition and method of using the composition for brazing high temperature niobium-based substrates, such as niobium-based refractory metal-intermetallic compositions (RMIC), including but not restricted to niobium-silicide composite alloys. The high temperature melting composition can include one or more alloys. The alloys include a base element selected from titanium, tantalum, niobium, hafnium, silicon, and germanium. The alloys also include at least one secondary element that is different from the base element. The secondary element can be selected from chromium, aluminum, niobium, boron, silicon, germanium and mixtures thereof. When two or more alloys are included in the composition, it is preferable, but not required, to select at least one lower melting alloy and at least one higher melting alloy.; The composition is preferably a homogemeous mixture of the two or more alloys combined in powder form.