  First-principles electronic-structure computes the lattice and elastic
constants of single-crystal TiB and NbB and changes with Nb, Ti, Al, and V
solutes. The data is built into an interpolation formula for lattice and
elastic constants of the quartenary (TiNbAlV)B with dilute Al and V
concentrations. The lattice and elastic constants of borides in two Ti alloys
containing Nb and Al are predicted from microprobe measurements.
