Tensile Strength Evolution and Damage Mechanisms of Al–Si Piston Alloy at Different Temperatures

Abstract

The Al-Si piston alloys always bear different temperatures because of its peculiar component structure and service condition. Therefore, the tensile strength, elongation to fracture, and corresponding damage mechanisms of Al12SiCuNiMg piston alloys (ASPA) have been investigated with in situ technique at different temperatures. The tensile properties show two-stage tendencies: the former stage (25-280 C) is determined by easily broken phases with inherent brittleness (such as primary Si), and the fracture behavior presents rapid brittle fracture after reaching the critical stress (about 430 MPa, based on in situ technique and the elastic stress field model). The later one (280-425 C) is dominated by particles debonding and θphase coarsening. The plastic deformation behavior, dynamic recovery, and flow process become more significant on account of thermal activation. The Consid ere criterion h ¼ K indicates that the transition of damage behaviors from insufficient local strength to insufficient matrix strength and the corresponding failure model shifts from brittle to ductile fracture. Based on the damage mechanisms, the elastic field model and thermal activation relation model have been established to characterize the strength of the ASPA at different temperature ranges.

Revealing the Effect of Local Connectivity of Rigid Phases during Deformation at High Temperature of Cast AlSi12Cu4Ni(2,3)Mg Alloys

“…This is in agreement with previous reports in which an increase in the fraction of decohesion between Si/matrix interfaces and matrix damage in shape of voids was also observed after deformation of Al-Si alloys at elevated temperature [33,34,38,39,40]. Decohesion is known to result from accumulation of plastic deformation of the matrix in the vicinity of rigid phases, while fracture of rigid particles occurs owing to incompatible stresses between rigid phase and matrix [33].…”

Microstructural Optimization of Fe‐Rich Intermetallic in Al–12 wt% Si–2 wt% Fe alloys by Adding Travelling Magnetic Fields

“…Al alloys, a recyclable material, are playing an important role in the national economic development because of its excellent comprehensive performance. [ 1 ] Among them, Al–Si alloys, such as the ZL109 Al alloy, are widely used as piston heads and pin bosses in engines, [ 2,3 ] due to its high strength to weight ratio, low thermal expansion coefficient, good thermal conductivity, and corrosion resistance. [ 4–6 ] Iron is the most common harmful impurity to restrict the recycling of Al–Si alloys, due to the large size Fe‐rich intermetallic produced during each cycle process.…”

On the Role of Hazard and Particle Failure Statistics on the Variation of Fracture Parameters of Ductile-Brittle Composites

“…Even for a pure polycrystalline material, one can distinguish ductile and brittle fracture, voids growth, transgranular and intergranular failure, shear band decohesion, crack nucleation due to twin interaction [1][2][3][4][5]. Non-homogeneous materials, such as metal-matrix composites, envisage yet a larger spectrum of failure modes, including cleavage of brittle particles embedded in a ductile matrix and matrix-particle decohesion [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22].…”

“…In this framework, the numerical simulations were mainly based on the "void cell computations" suggesting either periodic arrays of cells with spherical particles or more complex (but also regular) arrangements including several families of cells of different size, cells containing several voids, and variation of the voids shape [26][27][28][29][30][31]. On the other hand, numerous experiments showed that the fracture of composites depend on the heterogeneous distribution of particle sizes, shapes, and interparticle spacing, as well as the associated topology of the second phase [6][7][8][9][10][11][12][13][16][17][18][19][20][21][22][32][33][34]. Models considering real particle arrangements made it possible to examine the role of the material heterogeneity, in particular, the particles clustering and complex interconnected topologies, as well as the statistical aspect of fracture [17,[35][36][37][38][39][40][41].…”

“…The reason for the choice of this alloy for mechanical tests was two-fold. On the one hand, both the mechanical properties and microstructure of Al-Si alloys have been documented in the literature due to their wide applications (e.g., [6][7][8][9][10][11][12][13][17][18][19][20][21][22]41,45]). On the other hand, it is known that heat treatment can efficiently transform the interconnected coral-like Si phase characterizing the as-cast eutectic alloy into isolated particles with close-to-spherical shape [9,32,48].…”