Study on Interface Microstructure and Mechanical Performance of K403 Blade Repaired with Heterogeneous Material

doi:10.12068/j.issn.1005-3026.2025.20240019

Abstract

Abstract:

By taking K403 damaged blades as the substrate， IN718 alloy powder by laser cladding was used to repair and remanufacture the interface area between cladding layer and substrate. Based on the orthogonal tests， the laser cladding process for IN718 alloy was optimized， and the influence of the process parameters on the formation size and quality of the cladding layer was studied. The microstructure characteristics of the repaired interface area and the mechanism of crack formation were analyzed. The results show that cracks originate from the substrate regions and expand towards the cladding layer. The location of crack initiation is influenced by the shape of the molten pool， and the number of cracks is related to the morphology of the fusion zone. After heat treatment， the precipitates between the grains of the cladding layer transform from granular Laves phase to acicular phase δ. The interface area exhibits metallurgical bonding. The heat treatment has little effect on the K403 substrate， but it makes the hardness transition in the interface area smoother， and increases the hardness of the cladding layer by nearly 50%， the width of the heat affected zone is about 2.1 mm； the tensile strength is 731.7 MPa， and the elongation is 3.7%. The fracture type is a quasi-cleavage fracture dominated by brittle fracture.

Key words: laser cladding, heterogeneous material, K403 blade, interface microstructure, mechanical performance

CLC Number:

TH 161

Qi-zhen REN, Gui-ru MENG, Ya-dong GONG, Yuan-feng LI. Study on Interface Microstructure and Mechanical Performance of K403 Blade Repaired with Heterogeneous Material[J]. Journal of Northeastern University(Natural Science), 2025, 46(9): 102-112.

Figures/Tables 17

Table 1 Chemical composition of K403 substrate and IN718 powder (mass fraction)

元素	Cr	Fe	Mo	Nb	Ti	Al	Co	W	Si	Ni
K403基体	10~12	<2	3.8~4.5	—	2.3~2.9	5.3~5.9	4.5~6	4.8~5.5	—	余量
IN718粉末	19.23	19.3	3.05	5.14	0.99	0.58	<0.005	—	0.055	余量

Table 2 Thermophysical parameters of K403 and IN718

试验材料	K403
温度/℃	100	200	300	400	500	600	700	800	900	1 000
线膨胀系数×10^-6/C	11.3	12.3	12.3	12.6	12.9	13.0	13.4	13.8	14.3	15.1
热导率/（W·（m·C）^-1）	14.27	14.52	17.12	18.25	19.72	20.43	22.27	23.53	24.82	—
熔化温度/℃	1 260~1 338
密度/（g·cm^-3）	8.1
试验材料	IN718
温度/℃	100	200	300	400	500	600	700	800	900	1 000
线膨胀系数×10^-6/C	11.8	13.0	13.5	14.1	14.4	14.8	15.4	17.0	18.4	18.7
热导率/（W·（m·C）^-1）	14.7	15.9	17.8	18.3	19.6	21.2	22.8	23.6	27.6	30.4
熔化温度/℃	1 260~1 320
密度/（g·cm^-3）	8.24

Table 3 Orthogonal test scheme and results of laser cladding IN718 alloy

序号	P/W	v/（mm·min^-1）	f/（r·min^-1）	W/μm	H/μm	D/μm	W/H	η	HV
1	800	240	1.6	2 682.37	349.18	420.07	7.68	0.66	413.7
2	800	360	1.8	2 560.10	186.90	485.83	13.70	0.73	440.3
3	800	480	2	2 443.30	171.54	454.02	14.24	0.77	416.5
4	800	600	2.2	2 375.13	130.63	419.08	18.18	0.78	490.8
5	1 000	240	1.8	3 060.28	434.98	583.41	7.04	0.63	374
6	1 000	360	1.6	2 883.74	247.06	510.73	11.67	0.73	428.6
7	1 000	480	2.2	2 689.63	208.65	459.17	12.89	0.75	479.5
8	1 000	600	2	2 603.46	151.56	444.29	17.18	0.80	473.7
9	1 200	240	2	3 508.66	402.25	655.39	8.72	0.69	430.9
10	1 200	360	2.2	3 045.69	352.94	498.96	8.63	0.69	448.9
11	1 200	480	1.6	2 936.33	172.32	519.73	17.04	0.81	479.5
12	1 200	600	1.8	2 783.05	119.38	488.60	23.31	0.85	475.4
13	1 400	240	2.2	3 433.22	438.06	586.17	7.84	0.65	438.1
14	1 400	360	2	3 209.00	215.57	588.58	14.89	0.78	477.6
15	1 400	480	1.8	2 954.33	119.03	520.42	24.82	0.83	461.6
16	1 400	600	1.6	2 884.78	73.62	495.20	39.19	0.87	437.8

Fig.1 Location and dimensions of tensile sample

Fig.2 Range analysis diagram

Fig.3 Macro morphology of cladding layer under different process parameters

Fig.4 Influence of specific energy on microstructure of cladding layer

Fig.5 Formation positions of longitudinal cracks in different molten pool morphologies

Fig.6 Mechanism of liquefaction crack formation

Fig.7 Microstructure of cladding layer and substrate before and after heat treatment

Table 4 EDS chemical composition of each point in cladding layer and substrate after heat

测试点	Al	Ti	Cr	Fe	Co	Ni	Nb	Mo	W
A	1.25	3.70	14.32	10.29	—	40.89	23.90	5.65	—
B	1.70	2.34	17.64	12.41	—	60.96	2.64	2.31	—
C	0.46	0.82	16.90	15.13	—	54.86	8.83	3.00	—
D	0.20	0.96	14.01	12.40	—	56.78	12.61	3.05	—
E	0.40	0.69	19.92	17.99	—	54.69	3.60	2.70	—
F	0.01	40.21	1.97	—	0.08	2.69	—	16.55	38.48
G	5.30	2.45	10.11	—	4.70	69.02	—	3.08	5.34

Fig.8 Scanning electron microscopy of microstructure of sample section

Fig.9 Microhardness curves of interface area before and after heat treatment

Table 5 Tensile properties of specimens at room

样品

屈服强度

$R P 0.2 / M P a$

抗拉强度

$σ b / M P a$

断后伸长率

$δ / %$