The defects and residual tensile stress in laser cladding layer may cause crack propagation, and will decrease the fatigue resistance of components by laser cladding. Based on analyzing the forming mechanism of the crack and residual tensile stress during the process of laser cladding, a novel surface treatment technique which combines laser cladding with laser shot peening (LSP) was presented, the mathematical model of thermal stress induced by laser cladding was established, the mechanisms of improving the quality of cladding coating by LSP were studied. The results indicate that under the combination effects of high density dislocation microstructure and residual compressive stress, the defects of the cladding coating in the laser peened area were overcome effectively, and the rate of crack growth was delayed. Finally, the feasibility of the novel technique was validated by experiments, and the hardness and residual stress distribution in the peened and unpeened coating of laser cladding were compared.

1.
L.
Sexton
et al (
2001
)
Laser cladding of aerospace materials
,
Journal of Materials Processing Technology
122
,
63
68
.
2.
Wang
,
J.
,
Zou
,
S.K.
et al (
2005
)
Application of laser shock processing turbine engines
,
Applied Laser
25
(
1
),
32
34
.
3.
Omar
Hantamleh
et al (
2007
)
Laser and shot peening effects on fatigue crack growth in friction stir welded 7075-T7351 aluminium alloy joints
,
International Journal of Fatigue
29
,
426
430
4.
Zou
,
S.K.
&
Wang
,
J.
et al (
2002
)
Study on laser shock processing to decrease the fatigue crack growth rates of aluminium alloy
,
Aeronautical Manufacturing Technology
9
,
37
39
.
5.
Wu
,
L.S.
,
Zhu
,
P.D.
&
Cui
,
K.
(
1996
)
Effect of Ni content on cracking susceptibility and microstructure of laser-clad Fe-Cr-Ni-B-Si alloy
,
Surface and Coatings Technology
,
279
282
.
6.
Chen
,
J.
,
Yang
,
H.O.
,
Li
Y.M.
et al (
2002
)
The research on two kinds of cracking behaviour and mechanism of cladding in rapid laser forming process
,
Applied Laser
22
(
3
),
300
304
.
7.
Song
,
W.L.
,
Zhu
P.D.
,
Zhang
,
J.
et al (
1999
)
The effects of expansion coefficient of laser cladding layer on cracking sensitivity
,
Journal of Huazhong University of Science and Technology
17
(
1
),
42
44
.
8.
Li
,
S.
et al (
2007
)
Study on evaluation method of mechanical property of laser cladding layers
,
Metal Hotworking Technology
36
(
11
),
50
52
.
9.
Fu
,
G.Y.
et al (
2006
)
Analysis to flaw damaging and mechanism of laser coating under repeated impact load
,
China Mechanical Engineering
17
(
21
),
2296
2304
.
10.
Wang
,
R.Z.
(
2005
)
Residual stress and fatigue properties of spring
,
Physical Testing and Chemical Analysis Part A Physical Testing
41
(
11
),
541
548
.
11.
Nikitin
et al (
2004
)
High temperature fatigue behaviour and residual stress stability of laser-shock peened and deep rolled austenitic steel AISI 304
,
Scripta Materialia
50
,
1345
1350
.
This content is only available via PDF.
You do not currently have access to this content.