Abstract:The influence of heat treatment processes on the strength.hardnese and fatigue crack propagating rate of a Cu-Ni-Al-Ti alloy was studied.The results show that the ccoling rate after solution heat treatment has great influence on the properties of the alloy:namely,the larger the cooling rate,the higher the strength and the lower the plasticity.But the alloy can retain relativelyhigh strength even under air-cooling.With regard to the strength.it is advisable to adopt the following process:solution heat treatment+water cooling +cold deformation +aging.However,with regard to the combination of the strength,plasticity and fatigue crack propagating rate,it isadvisable to adopt the following process:solution heat treatment +air-cooling+cold deformation+aging.

Key words: Cu-Ni-Al-Ti alloy  heat treatment  strength  plasticity  fatigue crack propagatingrate  cold deformation