A semiconductor die attach composition with greater than 60% metal volume after thermal reaction consisting of: a. 80-99 percent by weight (wt%) of a mixture of metal particles comprising: i. 30-70 wt% of a lead-free, low melting point metal alloy particle composition comprising at least one LMP metal Y selected from the group consisting of Sn, Zn, Ga, In, and combinations thereof; and ii. 25-70 wt% of a high melting point particle composition comprising at least one metallic element M, selected from the group consisting of Cu, Ag, Pd, Au, Al, Ni, Be, Rh, Co, Fe, Mo, W, Mn, Pt and combinations thereof that is reactive with the at least one LMP metal Y at a process temperature T1 in the range of 100°C to 300°C, wherein the ratio of wt% of M to wt% of Y in the composition is at least 1.0, iii. 0-30 wt% of a metal powder additive A comprising Cu, Ag, In, Pd, Au, Ni, Ce, Pt or combinations thereof or comprising Be, Rh, Co, Fe, Mo, W, or Mn that has been alloyed, pseudo alloyed, or coated with a metal that can react with either M or Y and b. 1 to 20 percent by weight (wt%) of a fluxing vehicle which acts as a carrier for the metallic particles and removes and prevents the formation of metal oxides, wherein said fluxing vehicle consists of: i. a volatile portion consisting of a chemically inert solvent, and ii. not more than 50 wt% of a non-volatile portion comprising a combination of a carboxylic acid and a phenol, that becomes inert at T1, wherein said LMP particle composition does not contain bismuth beyond trace detectable levels. a. 80-99 percent by weight (wt%) of a mixture of metal particles comprising: i. 30-70 wt% of a lead-free, low melting point metal alloy particle composition comprising at least one LMP metal Y selected from the group consisting of Sn, Zn, Ga, In, and combinations thereof; and ii. 25-70 wt% of a high melting point particle composition comprising at least one metallic element M, selected from the group consisting of Cu, Ag, Pd, Au, Al, Ni, Be, Rh, Co, Fe, Mo, W, Mn, Pt and combinations thereof that is reactive with the at least one LMP metal Y at a process temperature T1 in the range of 100°C to 300°C, wherein the ratio of wt% of M to wt% of Y in the composition is at least 1.0, iii. 0-30 wt% of a metal powder additive A comprising Cu, Ag, In, Pd, Au, Ni, Ce, Pt or combinations thereof or comprising Be, Rh, Co, Fe, Mo, W, or Mn that has been alloyed, pseudo alloyed, or coated with a metal that can react with either M or Y and i. 30-70 wt% of a lead-free, low melting point metal alloy particle composition comprising at least one LMP metal Y selected from the group consisting of Sn, Zn, Ga, In, and combinations thereof; and ii. 25-70 wt% of a high melting point particle composition comprising at least one metallic element M, selected from the group consisting of Cu, Ag, Pd, Au, Al, Ni, Be, Rh, Co, Fe, Mo, W, Mn, Pt and combinations thereof that is reactive with the at least one LMP metal Y at a process temperature T1 in the range of 100°C to 300°C, wherein the ratio of wt% of M to wt% of Y in the composition is at least 1.0, iii. 0-30 wt% of a metal powder additive A comprising Cu, Ag, In, Pd, Au, Ni, Ce, Pt or combinations thereof or comprising Be, Rh, Co, Fe, Mo, W, or Mn that has been alloyed, pseudo alloyed, or coated with a metal that can react with either M or Y and b. 1 to 20 percent by weight (wt%) of a fluxing vehicle which acts as a carrier for the metallic particles and removes and prevents the formation of metal oxides, wherein said fluxing vehicle consists of: i. a volatile portion consisting of a chemically inert solvent, and ii. not more than 50 wt% of a non-volatile portion comprising a combination of a carboxylic acid and a phenol, that becomes inert at T1, i. a volatile portion consisting of a chemically inert solvent, and ii. not more than 50 wt% of a non-volatile portion comprising a combination of a carboxylic acid and a phenol, that becomes inert at T1,