A solid quarter is alleviating some of the concern surrounding this aerospace stock.Material sciences specialist ATI (ATI 16.42%) reported a strong first quarter, and its guidance implies that issues at Boeing are not softening demand for its products. Investors are relieved, sending ATI shares up 17% as of 2 p.m. ET.Steady results in a tough environmentATI makes high-performance materials for the aerospace, defense, healthcare, and energy markets. It is best known for the composite fibers used to replace h ...