A hybrid loader boom arm assembly for a loader work vehicle includes an arm assembly that includes a first beam formed from a lightweight material and a second beam formed from the lightweight material. The loader boom arm includes a connection assembly having a first steel plate and a pair of knee plates formed from the lightweight material. A portion of the first steel plate is received within the first beam and a second portion of the first steel plate is received within the second beam. The pair of knee plates cooperate to define a first channel that receives the end of the first beam and a second channel that receives the second end of the second beam. The first steel plate and the pair of knee plates are configured for interconnecting the first beam with the second beam.
