沉淀硬化镍基合金在低温至1600°F以上时具有良好的强度、延展性和耐腐蚀性。这些性能是通过添加许多合金剂获得的，包括铬、钴、铝、钛、钼、铌、硼和锆。通过操纵固溶处理和时效程序以及合金含量，机械性能可能在很大范围内发生变化。主要强化相为γ素（一种基于镍的沉淀）∋但其成分和动力学将随合金含量而变化，可能包括钛、铌，可能还包括钼。还发现了许多其他相，尤其是碳化物。 碳化物相形态对高温塑性起控制作用；然而，碳化物的形态和成分取决于合金、形成温度和之前的历史。 由于合金的强度和复杂性，焊接和焊后热处理已被证明是昂贵的问题。主要困难是微裂纹（焊接期间）和应变时效裂纹（焊后热处理期间）。除非采取额外预防措施，否则也会出现气孔、热裂纹和未熔合。 晶粒尺寸以及铅、硫、磷、锆、硼和稀土元素的增加会导致微裂纹或晶间裂纹（可能发生在焊接后冷却时）。 目前正在研究添加镁、锰和硅，以减少微裂纹倾向。这些裂缝通常无法无损检测。随着硬化剂含量的增加，合金之间的应变裂纹增加，随着焊后加热速率的增加，应变裂纹减少。最近对一种合金的研究揭示了热处理气氛在裂纹萌生中的作用。然而，不知道这是否普遍适用。许多用户正在努力建立可靠的测试程序，这对研究和筛选材料都有价值。感兴趣的方法包括热塑性测试、模拟热影响区测试和焊接循环修改- patch和Varestraint测试。时效母材的机械性能和可焊性之间的相关性不足。

Precipitation-hardenable nickel-base alloys possess good strength, ductility, and corrosion resistance from cryogenic temperatures to above 1600°F. These properties are obtained through the addition of many alloying agents including chromium, cobalt, aluminum, titanium, molybdenum, columbium, boron, and zirconium. Mechanical properties may be varied over a wide range through manipulation of the solution treating and aging procedures and alloy content. The principal strengthening phase is gamma prime (a precipitate based upon the Ni∋Al compound), but its composition and kinetics will vary with alloy content and it may include titanium, columbium, and possibly molybdenum. Many other phases, most notably the carbides, are also found. Carbide-phase morphologies exert control over elevated-temperature ductility; however, the morphologies and compositions of the carbides depend upon the alloy, temperature of formation, and prior history. As a result of the great strengths and complexities of the alloys, welding and postweld heat treating have proved to be expensive problems. The chief difficulties are microfissuring (during welding) and strain-age cracking (during postwelding heat treatment). Porosity, hot cracking, and lack of fusion are also encountered unless extra precautions are taken. Microfissuring, or intergranular cracking (probably occurring on cooling after welding) is encouraged by increasing grain size as well as lead, sulfur, phosphorus, zirconium, boron, and rare earth elements. Magnesium, manganese, and silicon are currently under investigation as additions for reducing the tendency towards microfissuring. These fissures cannot generally be detected nondestructively. Strainage cracking increases from alloy to alloy with increasing hardener content and decreases with increasing postweld heating rate. Recent studies with one alloy have disclosed the role of the heat-treating atmosphere in crack initiation. However, it is not known if this is generally applicable. Many users are endeavoring to establish reliable testing procedures that would be of value in both studying and screening material. The methods of interest include hot-ductility testing, testing simulated heat-affected zones, and modifications of the weld circle-patch and the Varestraint tests. Insufficient correlation has been developed between aged parent-metal mechanical properties and weldability.