DD3

HuaNickel DD3 is a nickel-based precipitation-hardening single-crystal superalloy, which belongs to the first generation of single-crystal superalloy. The alloy has good medium and high temperature properties and microstructure stability, as well as excellent resistance to cold and heat fatigue. The alloy composition is simple, does not contain scarce and precious elements, and the cost is low. Compared with the first generation of foreign single crystal alloy PWA1480, the mechanical properties are comparable, but the resistance to high-temperature oxidation and hot corrosion is poor. Compared with DZ403 alloy with similar composition, the endurance strength of 760°C and 100h is about 39MPa. The endurance strength of 1040°C and 100h is about 39MPa.

DD3Chemical composition：

	Ni	Cr	Co	W	Mo	AI	Ti	C	Fe	Mn	Si	P	S	Cu
Min	Bal	9	4.5	5	3.5	5.5	1.7				≤
Max		10	5.5	6	4.5	6.2	2.4	0.01	0.5	0.2	0.2	0.01	0.001	0.1

DD3Physical properties：

Density	8.2g/cm³
Melting point	1328℃~1376℃
Magnetic properties	not

Coefficient of linear expansion

θ/℃		20~300	20~400	20~500	20~600	20~700	20~800	20~900	20~1000	20~1100
α/(10-6℃-1)	[001]	12.38	12.96	13.38	13.92	14.36	14.66	15.30	16.14	17.16
	[011]	12.47	13.02	13.42	13.72	14.22	14.72	15.35	16.19	17.16
	[111]	12.62	13.19	13.55	13.82	13.95	14.82	15.47	16.37	17.35

Resilient performance

θ/℃		20	700	750	760	800	850	900	950	980	1000
E/GPa	[001]	115	89	82	97.5	85	90.5	80	74.5	64	61
	[011]			-—	162.0		144.0	—-	100.5	1224
	[111]	—	—	——	217.0	—	202.5	—	171.0	178①

DD3Mechanical properties：

Standard number	Variety	sampling	Heat treatment	Long-lasting performance			Tensile properties
				θ/℃	σ/MPa	τ/h	θ/℃	σ/MPa	δ₅/%	ψ/%
Q/6S 366	Master alloy	001Monocrystalline test sticks	standardHeat treatment	760	785	≥70	760	≥1030	≥3	≥3
				1000	195	≥70	900	≥835	≥6	≥6
				1040	165	≥70		—	—

DD3Alloy properties：

The surface of HuaNickel DD3 alloy parts needs to be infiltrated with Pt Al coating or M Cr Al Y coating to further improve the oxidation and corrosion resistance of the alloy. After long-term aging at 850°C, no σ phase precipitation was found.

DD3Uses of alloys：

HuaNickel  DD3 alloy is suitable for making gas turbine rotor blades operating below 1040°C and guide vanes working below 1100°C. An engine blade made of this alloy has passed the test run and flight test assessment of 3 benches, and has passed the material finalization identification.

DD3Process performance：

Welding process: vacuum brazing or diffusion connection welding.

Parts Heat treatment: notBal blades should be treated at 1250°C, 4h solution treatment under argon protection or vacuum, followed by forced cooling by argon blowing, the cooling rate should be greater than 300°C/min, and then 870°C, 32h aging, argon cooling by blowing.

Relevant standards：

GB/T14992  、Q/6S 366