Introduction 上游充道大粤 SHANGHAI JIAO TONG UNIVERSITY Ageing(时效)： ■ When a precipitation hardening alloy is quenched after solution treatment,its alloying elements will be trapped in solution,resulting in a soft metal. ■ Aging a“solutionized”(固溶处理)metal will allow the alloying elements to diffuse through the microstructure and form intermetallic particles. Natural aging(自然时效)：aging at room temperature Artificial aging(人工时效)：aging at elevated temperature K.Chen 4K. Chen Ageing (时效):  When a precipitation hardening alloy is quenched after solution treatment, its alloying elements will be trapped in solution, resulting in a soft metal.  Aging a “solutionized” (固溶处理) metal will allow the alloying elements to diffuse through the microstructure and form intermetallic particles. Natural aging (自然时效): aging at room temperature Artificial aging (人工时效): aging at elevated temperature Introduction 4