A critical appraisal of laser peening and its impact on hydrogen embrittlement of titanium alloys

Abstract

Many efforts have been made to understand the effects of hydrogen on titanium alloys, resulting in an abundance of theoretical models and papers. Titanium alloys are crucial advanced materials that provide an excellent combination of a high strength-to-weight ratio and good corrosion behaviour even though they are reasonable to corrosion attack. Titanium alloys are susceptible to hydrogen embrittlement when comes into contact with hydrogen, and galvanic pair with an active metal current, or the pH is greater than 12 or less than 3 or an impressed current. In view of the fact that hydrogen behaves differently with α and β phases, hydrogen degradation may vary markedly in titanium alloys. Hydrogen diminishes the corrosion and erosion resistance and fatigue life of in-service titanium components. A laser peening or laser shock peening is a novel technique for making the metal surfaces and sub-layers densify. It evokes that laser shock peening adoption results in yielding and plastic deformation, thereby creating high compressive residual stresses extending below the surface of the material which is desirable for hydrogen embrittlement resistance and reduction of crack initiation and growth of the component. This article is a review of information relating hydrogen embrittlement of titanium alloys and surface modification technique which influence the strength potential of titanium alloys.

Overview of Surface Modification Strategies for Improving the Properties of Metastable Austenitic Stainless Steels

“…Improved fatigue resistance, reduced stress corrosion cracking [73][74][75] Aerospace, automotive, medical, and nuclear industries [76] Improved surface properties, deeper layer of compressive residual stress [77] Limited to small areas, expensive [78] Submerged laser peening Improved fatigue resistance, reduced stress corrosion cracking [79,80] Aerospace, automotive, medical, and nuclear industries Reduced thermal damage to surface, deeper layer of compressive residual stress [81] Limited to submerged surfaces, requires specialized equipment [82] Surfi-Sculpt processing (three-dimensional laser surface modification)…”

Investigation on indentation, scratch, friction characteristics with hydrogen embrittlement of plasma ion nitrided Al alloy for hydrogen valve of fuel cell electric vehicle

“…The current density application condition for the hydrogen embrittlement research was 10 mA cm −2 . [11][12][13] In addition, hydrogen embrittlement was carried out in a 2 N H 2 SO 4 + 1 g l −1 Na 2 HAsO 4 ·7H 2 O electrolyte at RT for 3 and 6 h. Hydrogen embrittlement is a phenomenon caused by atomic hydrogen (H + ), and molecular hydrogen (H) can hardly penetrate aluminum alloys. 14) Therefore, the experimental solution contained arsenic (As), a hydrogen recombination inhibitor, to promote hydrogen embrittlement.…”

Additive manufacturing of titanium-based alloys- A review of methods, properties, challenges, and prospects

“…However, research has shown that the alloys' overall properties depend on the degree of impurity they contained, which adversely affects their plasticity [ 23 , 24 , 25 ]. Titanium alloys undergo plastic deformation when hydrogen, carbon, oxygen, and nitrogen are present [ 26 , 27 ]. In general, alloying elements play a crucial role in stabilizing its α or β phase [ 28 , 29 ].…”